Researchers improve efficiency of lowcost solar cells


first_img The researchers, Qijie Guo, Grayson M. Ford, Wei-Chang Yang, Bryce C. Walker, Eric A. Stach, Hugh W. Hillhouse, and Rakesh Agrawal, have published their study on the improved solar cells in a recent issue of the Journal of the American Chemical Society. They fabricated the solar cells from copper-zinc-tin-chalcogenide (CZTSSe), which is an Earth-abundant material, using a solution-based thin-film deposition method. Previous research has shown that these methods can provide high yields at lower manufacturing costs compared to other methods.The solar cell design is based on the researchers’ earlier study in which they demonstrated that solar cells fabricated using CZTS nanocrystals are potentially viable, although they had efficiencies of less than 1%. Here, the researchers made significant improvements to the design by tuning the composition of the nanocrystals as well as developing a more robust thin-film coating method.After synthesizing the nanocrystals and applying them on a substrate for a total film thickness of 1 micrometer, the researchers observed that the nanocrystal film featured large, densely packed grains, which leads to improved solar cell efficiency. In testing, the solar cells could achieve a total area efficiency of 7.2%. As coauthor Hugh Hillhouse explained, the total area efficiency refers to the entire cell, rather than just the “active area.””It is the total area efficiency that matters most,” he told PhysOrg.com. “Some people report an ‘active area’ efficiency, which only includes areas that the light reaches. However, all thin film solar cells are made with metal contacts that block the light from reaching some areas. When you include this loss, we use the term ‘total area’ efficiency. It is the most fair and important efficiency.”The 7.2% efficiency was reached after “light soaking” for 15 minutes under one-sun illumination; when the light was turned off, the efficiency dropped to 6.89%. “Light soaking simply means that we shine normal intensity simulated sunlight on the cell for a period of time before we make the measurement,” Hillhouse said. “Most likely, the light soaking allows photogenerated carriers to fill traps, shift the quasi-Fermi levels, and/or screen barriers created by band offsets. It doesn’t present a problem since real solar cells are naturally light soaked – they sit in the sun.”Although currently there are no CZTS or CZTSSe solar cells on the market for comparison, the solar cells in this study are very competitive with other fabrication methods.“The best cells formed by vacuum processes have only reached 6.7%,” Hillhouse said. “Typically, solar cells produced by vacuum-based processes have been more efficient, but also more expensive. For the case of CZTS, the solution phase approach (our nanocrystal route and IBM’s hydrazine route) is more efficient.”One potential area for improvement for these solar cells lies in improving their low quantum efficiency for light of longer wavelengths (i.e., the near-infrared range). The researchers attempted to improve this efficiency by increasing the thickness of the absorber, although their initial experiments showed that thicker absorber layers also had increased resistance. In the future, they plan to optimize the fabrication for thicker films, which could further increase the overall efficiency.“There is a lot of compositional freedom in the CZTSSe system, and it is likely that the optimum compositions, device structure, and processing conditions have not yet been found – but we are working on it,” Hillhouse said. Copyright 2010 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Structure of plastic solar cells impedes their efficiency, researchers find Citation: Researchers improve efficiency of low-cost solar cells (2010, December 7) retrieved 18 August 2019 from https://phys.org/news/2010-12-efficiency-low-cost-solar-cells.html (PhysOrg.com) — As part of the recent progress in improving solar cells for widespread use, researchers from Purdue University have designed solar cells made of low-cost, abundant materials that are easily scalable and very stable. The researchers have increased the solar cells’ total area efficiency to 7.2% and plan to make further improvements in the future. More information: Qijie Guo, et al. “Fabrication of 7.2% Efficient CZTSSe Solar Cells Using CZTS Nanocrystals.” J. Am. Chem. Soc. ASAP. DOI: 10.1021/ja108427b Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. This image shows a cross-section of a CZTSSe thin film solar cell. The film exhibits densely packed grains, which leads to a high efficiency. Image credit: Qijie Guo, et al. ©2010 American Chemical Society.last_img read more

Researchers theorize cold compression of graphite results in new superhard carbon allotropes


first_img © 2012 PhysOrg.com Crystal structure of H-carbon(a), initial AB stacking graphite supercell for H-carbon (b) and side view containing five and seven carbon rings of H-carbon (c). Crystal structure of S-carbon (d), initial AB stacking graphite supercell for Scarbon (e) and side view containing five and seven carbon rings of S-carbon (f). Image from arXiv:1203.5509v1 (PhysOrg.com) — Researchers in China have used math calculations to predict that under cold compression, two new carbon allotropes may be formed. In their paper pre-published on arXiv, the team describes how the two new allotropes would have a hardness factor somewhere between graphite and diamond. New carbon allotrope could have a variety of applications This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. More information: New Superhard Carbon Phases Between Graphite and Diamond, arXiv:1203.5509v1 [cond-mat.mtrl-sci] arxiv.org/abs/1203.5509AbstractTwo new carbon allotropes (H-carbon and S-carbon) are proposed, as possible candidates for the intermediate superhard phases between graphite and diamond obtained in the process of cold compressing graphite, based on the results of first-principles calculations.Both H-carbon and S-carbon are more stable than previously proposed M-carbon and W-carbon and their bulk modulus are comparable to that of diamond. H-carbon is an indirect-band-gap semiconductor with a gap of 4.459 eV and S-carbon is a direct-band-gap semiconductor with a gap of 4.343 eV. S-carbon is even more stable than the Z-carbon which is the most table carbon phase proposed recently. The transition pressure from cold compressing graphite is 10.08 GPa and 5.93 Gpa for H-carbon and S-carbon,respectively, which is in consistent with the recent experimental report.via Arxiv Blog Explore further An allotrope is a substance that is essentially the same as another, with just minor differences in structure. Thus, both graphite and diamonds are allotropes of carbon. In their paper, the research team shows, via mathematical calculations, that subjecting a graphite allotrope to varying degrees of both cold and high pressure, would result in small changes to the structure, resulting in two new carbon allotropes.Prior to this work, other researchers have theorized that applying pressure at room temperature (more than 10 GigaPascals) to graphite would also result in structural changes, creating new allotropes (M10-carbon, monoclinic M-carbon, orthorhombic W-carbon or cubic body center C4 carbon) though thus far it isn’t clear if those changes would remain in effect after the pressure is removed.The new allotropes that theoretically would be produced by exerting pressure under cold conditions, which the team have called H-carbon and S-carbon, would also apparently be more stable than the allotropes produced without the cold, and even more stable, they say, than graphite under pressure, which means they would be more likely to survive in their compressed state after being returned to normal conditions.By using mathematical models to predict the creation of new carbon allotropes, researchers pave the way for real world experiments to find out if the new materials would truly exist, and if so, to what purpose they might be used. New carbon allotropes would have different optical properties, such as their degree of transparency, for example or how well they reflect light, than already well understood allotropes that are already being used in real world applications,. Such properties in new allotropes, if they can be caused to persist under reasonable conditions, might lead to new and better products.But before researchers begin trying to produce these new allotropes, more theoretical work will need to be done to see if there are others out there still waiting to be discovered. Citation: Researchers theorize cold compression of graphite results in new superhard carbon allotropes (2012, March 30) retrieved 18 August 2019 from https://phys.org/news/2012-03-theorize-cold-compression-graphite-results.htmllast_img read more

Psychologists say Facebook Twitter harden gender walls


first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Psychologists say Facebook, Twitter harden gender walls (2012, June 25) retrieved 18 August 2019 from https://phys.org/news/2012-06-psychologists-facebook-twitter-harden-gender.html Explore further Adding to a cynic’s file of Hardly-Shocking research is a new study out from the University of Bath that reports women are more attracted to social-networking sites than are men, who learn more toward Internet sites that carry games and gambling. Where the study does merit interest, however, is that it is a ten-year follow-up study that explores what if any changes have occurred since its first examination of gender differences in Internet usage in 2002. © 2012 Phys.Org Journal information: Cyberpsychology, Behavior, and Social Networking The paper, “Gender, Internet experience, Internet identification and Internet anxiety: a ten year follow-up,” appears in Cyberpsychology, Behavior and Social Networking. Dr. Richard Joiner is the lead author.”In our previous research we had found no gender differences in the use of the Internet for communication, whereas in the current study we have found that females use the Internet for communication than males and were using social network sites more than males.”As the study authors point out, the Internet has changed considerably since their 2002 look, with the introduction of Facebook, Twitter and deluge of smartphones. Interestingly, some theorists claimed early on that technology advancements would lessen gender differences and that the Internet would be an equalizer, but these authors have found otherwise.Women were more attracted to social networking sites such as Facebook and Twitter and were significantly more likely to use email and telephone over the web than males; males were more likely than females to use newsgroups, gaming and gambling sites.The University of Bath study examined results from 501 first-year psychology undergraduate students from six UK universities. There were 389 females and 100 males. Twelve participants did not specify their gender. The sample was chosen to match as closely as possible the 2002 study sample.Product vendors and marketing agencies, among others, are most likely to pay attention to Internet gender-usage studies. The takeaway of the University of Bath Department of Psychology study is that its authors say the gap has grown wider between the way in which men and women use the Internet.“Our findings indicate that rather than transcending or overcoming gender differences in wider society, Internet use by males and females seems to reflect, and in some instances even exacerbate, these broader trends.”They also express support of the view that gender differences in the use of the Internet reflect gender differences in wider society and are thus “more resistant to change than some people have suggested.” More information: opus.bath.ac.uk/30228/ Examining gender disparities in injury mortality; men at exceptional risklast_img read more

Researchers find blocking Internet pirating sites is not effective


first_img Citation: Researchers find blocking Internet pirating sites is not effective (2013, January 10) retrieved 18 August 2019 from https://phys.org/news/2013-01-blocking-internet-pirating-sites-effective.html Credit: Tobias Lauinger et al. Researchers find most BitTorrent users being monitored Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. There has been a lot of press coverage of pirating on the Internet and corporate efforts to stop it, yet to date, the researchers note, very little if any research has been conducted to determine if the methods used are effective. To find out for themselves, the team began monitoring the availably of thousands of files spread across the Internet via popular file-hosting sites. They noted that as sites were blocked, availability of certain files dropped, but only for a short time – soon other sites picked up the slack and the files formerly found on the blocked site soon became available on other hosting sites, making the blocking action moot.As part of their research, the team also noted that the shutdown of the wildly popular Megaupload site did little to curb the spread of content that users had previously found there. They suggest that if anything, shutting down arguably the most popular file sharing site on the Internet led to a more fractured landscape, with many more small sites sharing files, making stopping piracy even more difficult. The researchers also counted the number of file-sharing sites that are believed to currently host pirated content and found over 10,000 domain names covering more than 5,000 IP addresses.After analyzing their data, the research team concluded that blocking file-hosting sites is ineffective and the practice has done little to lessen the number of illegally shared files available for download from such sites. They suggest that taking away the ability to process payments from such services would likely be much more effective, though they also note the difficulty content providers might find in separating legitimate file-hosting sites from those that share pirated material. Another approach they suggest is that a more reasonable alternative be created that reduces demand, similar to the model that has been created for downloadable music. © 2013 Phys.org More information: Clickonomics: Determining the Effect of Anti-Piracy Measures for One-Click Hosting (paper PDF) (Phys.org)—Researchers at Boston’s Northeastern University have conducted a study on the effectiveness of anti-piracy measures taken by content providers to deter the illegal sharing of files on the Internet. Their research shows that tactics such as blocking sites by seizing domains names does little to curb the sharing of protected files. They suggest that providers instead focus on blocking the income stream such sites generate.last_img read more

Closer look reveals mechanism behind curling of ancient scrolls


first_img Journal information: Physical Review Letters Citation: Closer look reveals mechanism behind curling of ancient scrolls (2014, January 29) retrieved 18 August 2019 from https://phys.org/news/2014-01-closer-reveals-mechanism-ancient-scrolls.html People whose job it is to protect ancient art face a variety of destructive elements, from moisture and chemicals in the air to microbes that eat away at fabrics and paints. With scrolls, there is another problem—curling that results when fabric or paper is rolled up for storage. In addition to being unsightly, curling tends to damage the art that is being stored. For that reason, conservationists have been searching for thousands of years for ways to prevent it from happening. In this new effort, the researchers appear to have made progress in that direction by revealing what happens when material is rolled up and why it curls as a result.To find out what really happens when flat material is rolled up, the researchers subjected a variety of materials (plastics and paper) to rolling, watching very closely to see what changes came about. They also created computer models meant to replicate what occurred as rolling was applied. The one element they found that was common to all the test subjects was that the backing material underwent more stress than other parts and as a result was pulled slightly apart. When the material was unrolled (for viewing, for example) the material “tried” to shrink back to its original shape causing an expansion along its width—the end result being the familiar and undesired curling.The findings by the team suggests that a way to reduce curling is to add a backing to the underside of scrolls with material that has fibers that align with the long edges. Another approach would be to create tiny perforations in the backing to reduce stress and thus stretching—a technique that has been used on Japanese artwork for generations—they use a stiff brush.Interestingly, the work by the team in China may have a modern application—reducing curling on flexible electronic displays—a problem that consumers have recently been noting in newly developed bendable phone screens. © 2014 Phys.org Explore further More information: Curling Edges: A Problem that Has Plagued Scrolls for Millennia, Phys. Rev. Lett. 112, 034302 (2014) prl.aps.org/abstract/PRL/v112/i3/e034302AbstractQi-Wa refers to the up curl on the lengths of hand scrolls and hanging scrolls, which has troubled Chinese artisans and emperors for as long as the art of painting and calligraphy has existed. This warp is unwelcome not only for aesthetic reasons, but its potential damage to the fiber and ink. Although it is generally treated as a part of the cockling and curling due to moisture, consistency of paste, and defects from the mounting procedures, we demonstrate that the spontaneous extrinsic curvature incurred from the storage is in fact more essential to understanding and curing Qi-Wa. In contrast to the former factors whose effects are less predictable, the plastic deformation and strain distribution on a membrane are a well-defined mechanical problem. We study this phenomenon by experiments, theoretical models, and molecular dynamics simulation, and obtain consistent scaling relations for the Qi-Wa height. This knowledge enables us to propose modifications on the traditional mounting techniques that are tested on real mounted paper to be effective at mitigating Qi-Wa. By experimenting on polymer-based films, we demonstrate the possible relevance of our study to the modern development of flexible electronic paper.center_img Credit: Sun-Hsin Hung/National Palace Museum, Taipei Horsetail spores found able to ‘walk’ and ‘jump’ (w/ Video) (Phys.org) —A team of researchers in China has uncovered the reason for long side curling of scrolled artwork. In their paper published in Physical Review Letters, the researchers describe how experiments they conducted with various materials showed that curling results from stretching of backing material. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Researchers build single molecule microphone that can detect proton size displacements


first_img(Phys.org) —A trio of researchers in the Netherlands has built a “microphone” out of just a single molecule that is capable of detecting displacements as small as a single proton. In their paper published in Physical Review Letters, Yuxi Tian, Pedro Navarro, and Michel Orrit describe how they embedded a single molecule in a crystal lattice along with a vibrating mechanism to create a new type of device capable of detecting vibrations at the nanoscale. (a) Sample mounting: an anthracene crystal doped with DBT was attached to the quartz crystal tuning fork. (b) The ZPL of a single DBT molecule is shifted upon deformation of its surrounding host crystal, as shown in (c) and (d). The real deformations are three-dimensional and much more complicated, as molecules can also rotate and be distorted. Credit: Phys. Rev. Lett. 113, 135505 – Published 26 September 2014 More information: Single Molecule as a Local Acoustic Detector for Mechanical Oscillators, Phys. Rev. Lett. 113, 135505 – Published 26 September 2014. journals.aps.org/prl/abstract/ … ysRevLett.113.135505ABSTRACTA single molecule can serve as a nanometer-sized detector of acoustic strain. Such a nanomicrophone has the great advantage that it can be placed very close to acoustic signal sources and high sensitivities can be achieved. We demonstrate this scheme by monitoring the fluorescence intensity of a single dibenzoterrylene molecule in an anthracene crystal attached to an oscillating tuning fork. The characterization of the vibration amplitude and of the detection sensitivity is a first step towards detection and control of nanomechanical oscillators through optical detection and feedback. Vibrational motion of a single molecule measured in real time Explore further Citation: Researchers build single molecule ‘microphone’ that can detect proton size displacements (2014, October 3) retrieved 18 August 2019 from https://phys.org/news/2014-10-molecule-microphone-proton-size-displacements.htmlcenter_img The researchers describe their device as a nanomicrophone, though it might best be shortened to just nanophone, as it picks up, or detects vibrations at the nanoscale. In either case, the effort was based on work conducted by a team in France recently who found that the electronic state of a molecule designated as a guest in a host matrix of another type of molecule, could be influenced by the matrix in such a way as to reveal vibrational properties of the matrix—finely enough to allow its use as a type of extremely miniature microphone.To build their micronanaphone, the researchers embedded individual dibenzoterrylene (DBT) molecules in a anthracene crystal lattice (with a low enough concentration to prevent the DBT molecules from touching). The crystal was then glued to a bit of quartz to act as a tuning fork. When the quartz was made to vibrate via an electric current it caused vibrations in the lattice which impacted the DBT molecule. In response the molecule changed how much it fluoresced (when excited by a laser), offering a way to measure how much vibration was occurring by degree of fluorescence. The team found they could focus on just one of the DBT molecules at a time because of imperfections in the crystal, which meant the final microphone was actually just one molecule in size.To test their device, the researchers stimulated the quartz in such a way as to fine tune the vibrations, measuring what they observed with just one molecule, photon by photon, over a full second and found that the device was able to accurately describe the amount of distortion occurring in the lattice. The researchers believe their micronanophone could be used for measuring either chemical or nano sized systems and because it’s so sensitive it could even be used to measure quantum effects in various structures such as extremely tiny cantilevers. One limitation is that the device only works at very low temperatures. © 2014 Phys.org This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Journal information: Physical Review Letterslast_img read more

Fossils from ancient extinct giant flightless goose suggests it was a fighter


first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Reconstruction of Garganornis ballmanni Meijer, 2014 based on the newly described fossil remains. This reconstruction is based on a generic Western Palaearctic Goose with short and robust tarsometatarsus, short toes and very short wings according to the known elements of Garganornis ballmanni. Illustration made by Stefano Maugeri. Credit: Royal Society Open Science (2017). DOI: 10.1098/rsos.160722 (Phys.org)—A small team of researchers from Italy, Norway and Austria has found evidence of an ancient extinct goose relative that once lived in what is now central Italy. In their paper published in Royal Society Open Science, the team describes the fossils they found, what they suggest the bird once looked like and possibly how it behaved. Giant prehistoric bird fossils found in Antarctica Explore further Citation: Fossils from ancient extinct giant flightless goose suggests it was a fighter (2017, January 13) retrieved 18 August 2019 from https://phys.org/news/2017-01-fossils-ancient-extinct-giant-flightless.htmlcenter_img Journal information: Royal Society Open Science The fossils were found in the Gargano region near the town of Scontrone in central Italy, a place that prior research has shown was an island in the Mediterranean during the time that the bird was alive—approximately 6 to 9 million years ago. Its bones suggest it weighed approximately 22 kilograms and stood approximately one and a half meters tall. But its wings were perhaps too small to allow the bird to fly. The researchers suggest this is common in evolution, especially on islands where birds no longer rely on flight to escape predators. The large size, the researchers note, also suggests it was not an aquatic bird and perhaps lived in a forested area where it clearly had no problems finding enough food for itself and its offspring. Its wings also had carpal knobs (hard and rounded skin) on the carpometacarpus bone (the one on the end akin to the hand in humans)—they are used by modern birds to fight with one another. For that reason, the researchers suggest the ancient bird was likely a fighter, as well. They have dubbed it Garganornis ballmanni.Modern birds with carpal knobs also include some ducks and geese that commonly fight one another over territorial rights. There was also another bird, the Rodrigues solitaire, now extinct, which was known to fight so ferociously that pairs of them would break each other’s bones. The researchers suggest that G. ballmanni likely fended off any attackers by virtue of its large size, but it would likely also have had to fight with others for another precious resource: fresh water. That would mean that it was likely aggressive as well, a trait not uncommon in modern geese.The fossils also represent the first bird remains to be found at the dig site at Scontrone. More information: Marco Pavia et al. The extreme insular adaptation ofMeijer, 2014: a giant Anseriformes of the Neogene of the Mediterranean Basin, Royal Society Open Science (2017). DOI: 10.1098/rsos.160722AbstractNew skeletal elements of the recently described endemic giant anseriform Garganornis ballmanni Meijer, 2014 are presented, coming from the type-area of the Gargano and from Scontrone, southern and central Italy, respectively. The new remains represent the first bird remains found at Scontrone so far, and another shared element between these two localities, both part of the Apulia-Abruzzi Palaeobioprovince. The presence of a very reduced carpometacarpus confirms its flightlessness, only previously supposed on the basis of the very large size, while the morphologies of tarsometatarsus and posterior phalanges clearly indicate the adaptation of G. ballmanni to a terrestrial, non-aquatic, lifestyle. Its very large body size is similar to that observed in different, heavily modified, insular waterfowl and has been normally interpreted as the response to the absence of terrestrial predators and a protection from the aerial ones. The presence of a carpal knob in the proximal carpometacarpus also indicates a fighting behaviour for this large terrestrial bird species. © 2017 Phys.orglast_img read more

Efficient and stable emission of warm white light from leadfree halide double


first_img White light emission from a single emitter layer is of interest in lighting applications due to its simplicity compared to multiple emitters. Typically, broadband and white light emissions originate from self-trapped excitons (STEs) existing in semiconductors with localized carriers and a soft lattice. The authors focused on the double perovskite Cs2AgInCl6 as a promising material that emits warm white light due to its broad spectrum and all-inorganic, lead-free nature. The study optimized the alloy to form Cs2(Ag0.6Na0.4)InCl6 with a small percentage of bismuth doping to emit warm white light with increased quantum efficiency for more than 1000 hours. Materials for lighting applications can be defined as those emitting a “warm” white light for indoor applications and “cold” white light that approximates the visible region of the solar spectrum. In the study, Luo et al first sought to understand the origins of broadband emissions in Cs2AgInCl6 using mathematical modeling and computational studies to relax the lattice and represent self-trapped excitons (STEs) to investigate exciton-phonon coupling. Such systems will be fundamental to engineer the next generation of energy-efficient and cost-effective lighting and display technologies. A self-trapped exciton (STE) is defined as a bound electron-hole pair carrier that can dramatically enhance luminescence, energy transport and lattice defect formation in the crystal. The researchers found that STEs in the double perovskite Cs2AgInCl6, arose from strong Jahn-Teller distortion of the integral AgCl6 octahedron complex. The trapped excitons had a similar orbital character to the free exciton, indicating parity-forbidden transition (arising due to disruption of the centre of symmetry). The theoretical analysis showed an extremely low photoluminescence quantum yield (PLQY) for pure Cs2AgInCl6. To enhance the PLQY for practical applications as broadband materials, the system had to be modified, specifically by breaking parity-forbidden transition to manipulate the symmetry of the STE wavefunction. Explore further Lighting it up: A new non-toxic, cheap, and stable blue photoluminescent material Computational studies of self-trapped excitons (STEs) in Cs2AgInCl6. a) GW band structure of the double perovskite crystal (Cs2AgInCl6). The orbital characters and the free-exciton wavefunction are plotted as a fat-band structure. The green, blue, cyan and red colors denote the Cl 3p, Ag 4d, In 5s and Ag 5s orbitals. The magenta circles represent the lowest free-exciton amplitude. b) STE in Cs2AgInCl6, Cs atoms are omitted for clarity. The cyan and magenta isosurfaces represent the electron and hole orbital densities respectively. The electron state (red dashed circle) is extended and the hole state (black dashed circle) is compact, consistent with the small effective mass of the conduction band seen in (a). The inset shows the Jahn-Teller distortion of the AgCl6 octahedron. The hole isosurface is obvious and electron isosurface invisible due to its small density. c) Configuration coordinate diagram for the STE formation; Est, Ed and EPL are self-trapping, lattice-deformation and emission energies. d) The calculated photoluminescence spectrum compared with the experimental result. The calculated curve was shifted to align its maximum with that of the experimentally measured curve for better comparison. Credit: Nature, doi: https://doi.org/10.1038/s41586-018-0691-0 White light emission from Cs2Ag1−xNaxInCl6. a) Luminosity function (dashed line) and photoluminescence spectra (solid lines) of Cs2Ag0.6Na0.4InCl6 measured at different temperatures from 233 K to 343 K. b) Photoluminescence stability of Cs2Ag0.60Na0.40InCl6 against continuous heating on a hotplate, measured after cooling to room temperature. c) Operational stability of Cs2Ag0.6Na0.4InCl6 down-conversion devices measured in air without any encapsulation. The boxplot showed the results for the different samples measured separately with the box edges representing quartiles and band in the box representing the mean and maximum data. d) XRD patterns of a Cs2Ag0.6Na0.4InCl6 film (black line) and powder (red line). The inset shows a 300 nm thick quartz substrate and 500 nm thick Cs2Ag0.6Na0.4InCl6 films under 254 nm UV illumination. Credit: Nature, doi: https://doi.org/10.1038/s41586-018-0691-0. Since lattice mismatch between the two perovskites (Cs2AgInCl6 andCs2NaInCl6) was very low (0.3 percent) the scientists anticipated Na+ incorporation would occur without detrimental defects or phase separation. For the synthesis, CsCl, NaCl, AgCl and InCl3 precursors were mixed into an HCl solution in a hydrothermal autoclave. The mixture was heated for a defined period of time and cooled down to result in a final white precipitate product (90 percent yield). The pure double perovskite phase was confirmed using X-ray diffraction patterns (XRD) of a series of product compositions. The results agreed with plasma optical emission spectrometry (ICP-OES). The results were also in agreement with similar alloying experiments that were previously conducted with lithium (Li). The study thus suggested a general trend for alkali-metal-induced photoluminescent enhancement in double perovskites. Photoluminescence spectra were recorded for a series of product powders by varying the temperature of the measurements. The authors optimized the Na content alongside bismuth (Bi3+) doping to improve the crystal quality and slow cooling to obtain the highest PLQY (85 ± 5 percent) recorded thus far for white-light-emitting materials to form the optimally alloyed Cs2Ag0.6Na0.4InCl6 in the study. More information: Jiajun Luo et al. Efficient and stable emission of warm-white light from lead-free halide double perovskites, Nature (2018). DOI: 10.1038/s41586-018-0691-0 Yiru Sun et al. Management of singlet and triplet excitons for efficient white organic light-emitting devices, Nature (2006). DOI: 10.1038/nature04645 Zewen Xiao et al. Searching for promising new perovskite-based photovoltaic absorbers: the importance of electronic dimensionality, Materials Horizons (2016). DOI: 10.1039/C6MH00519E Citation: Efficient and stable emission of warm white light from lead-free halide double perovskites (2018, November 19) retrieved 18 August 2019 from https://phys.org/news/2018-11-efficient-stable-emission-white-lead-free.html Characterization of Cs2AgxNa1−xInCl6 with different Na content. All samples were doped using a small amount of (0.04 percent) Bi and the composition determined using ICP-OES. a) XRD patterns of Cs2AgxNa1−xInCl6 powders with different Na content were obtained. The Asterix marks the (III) diffraction peak, θ diffraction angle and au – arbitrary units. b) Optical absorption (solid lines) and photoluminescence (dashed lines) spectra of pure Cs2AgInCl6 and Cs2Ag0.6Na0.4InCl6. c) Activation energy and PLQY of Cs2AgxNa1−xInCl6 powder vs. Na content. The dashed lines guide the eye. d) Excitation spectra of photoluminescence measured at different wavelengths. e) Emission intensity vs. excitation power for Cs2Ag0.6Na0.4InCl6. f) Transient absorption spectra for Cs2Ag0.6Na0.4InCl6 (laser pulse of 325 nm), ∆ A/A is optical density. The irregular peaks located at ~650 nm is from frequency doubling of the pumping light. Credit: Nature, doi: https://doi.org/10.1038/s41586-018-0691-0. A practical approach to achieve this was via partial substitution of Ag with an element that could sustain the double perovskite structure. The substitute required a distinctively different electronic configuration to Ag, such as a group-IA element or alkali metal. The scientists therefore explored alloying Na into Cs2AgInCl6 to form pure Cs2NaInCl6, which demonstrated broadband emission on substitution but with very low efficiency due to strong phonon emission, requiring optimization of the Na content in the complex. Photoluminescence excitation (PLE) spectra confirmed STE origin of the white emission to experimentally confirm the calculated time-scale of exciton self-trapping. The Na perovskite (Cs2Ag0.6Na0.4InCl6) exhibited linear dependence on the photoexcitation power. Additional theoretical tests were done to understand how PLQY varied as a function of the Na content. As the Na content increased, the transition dipole moment increased and then decreased to support the composition-dependent PLQY observed in the study. The electron wavefunction of the STEs was also compared before and after alloying with Na. Incorporating Na broke the inversion symmetry of the Cs2AgInCl6lattice, changing the electron wavefunction at the Ag site from symmetric to asymmetric. Two factors contributed to the decrease in PLQY on further increase of the Na content. The first was orbital overlap between electrons and holes of the STEs upon increased Na content. The second reason for the observed decrease in PLQY with increased Na was due to increased non-radiative loss in the Na-rich alloy. The scientists then developed a white light emitting diode (LED) by directly pressing the Na perovskite powders on to a commercial ultraviolet LED chip, without epoxy or silica encapsulation for protection. With the contribution from the blue light of the UV LED chip the device demonstrated a color temperature of 4,054 K to fulfill requirements for indoor lighting. When the white LED was operated for more than 1000 hour in air, negligible degradation was observed. The outstanding photometric performance combined with easy manufacture indicated promise for white-phosphor lighting applications. In this way, the scientists presented a new strategy to produce broadband emission associated with the STEs for single-material based white-light electroluminescence, allowing prototype double-perovskite based electroluminescence device formation. To increase electroluminescence performance in the future, further research should focus on optimizing the emitting-layer quality of the Cs2Ag0.6Na0.4InCl6 films. The study showed that alloying Na into Cs2AgIn Cl6 broke parity-forbidden transition as anticipated to reduce its electronic dimensionality and enable efficient white light emission via STEs.The white light emitting material also demonstrated low cost manufacture and exceptional stability as a promising solid-state lighting platform. The authors believe that such halide double perovskites hold great possibility for applications in display and lighting after further study to realize their full potential. The results will stimulate research on single-emitter-based white-light-emitting phosphors and diodes to generate the next-generation of lighting and display technologies. One-fifth of global electricity consumption is based on lighting; efficient and stable white-light emission with single materials is ideal for applications. Photon emission that covers the entire visible spectrum is, however, difficult to attain with a single material. Metal halide perovskites, for instance, have outstanding emission properties but contain lead, and therefore yield unsatisfactory stability. A new report published by Jiajun Luo and co-workers details a lead-free double perovskite that exhibited stable and efficient white light emission. In its mechanism of action, the material produced self-trapped excitons (STEs) due to Jahn-Teller distortion of the AgCl6 octahedron in the excited state of the complex, observed when investigating exciton-phonon coupling in the crystal lattice. The results are now published in Nature. A key challenge for lighting applications is the parameter of emission stability. The Cs2Ag0.6Na0.4InCl6perovskite showed stable emission in the study with little emission degradation. When the powder was annealed to a hotplate, only minimal photoluminescence decay of the white emission was observed, the authors proposed that the observations may be due to strongly bound excitons and a nearly defect-free lattice that prevented photoluminescence quenching while resisting thermal stress. Schematically visualizing the phonon band structure of Cs2AgInCl6 and the zone-center Jahn-Teller phonon mode (inset). The Jahn-Teller phonon mode coupled to the photoexcited excitons were responsible in the formation of self-trapped excitons in the Cs2AgInCl6 complex. Credit: Nature, doi: https://doi.org/10.1038/s41586-018-0691-0 Journal information: Nature © 2018 Science X Network Mechanistic investigation of PLQY in Cs2Ag1−xNaxInCl6. a) Transition dipole moment (µ) in Cs2Ag1−xNaxInCl6 as a function of Na content in the system. b) Parity change of the electron wavefunction of the STE before and after Na incorporation (pure and alloy). The cyan and magenta isosurfaces indicate electrons and holes c) Configurations showing strengthened STE confinement by the surrounding NaCl6 octahedra. d) STEs in Na-rich Cs2Ag1−xNaxInCl6. The STE is located in two neighboring octahedra. e) Configuration coordinate diagram of the STE formation in Cs2NaInCl6 (inset). Credit: Nature, doi: https://doi.org/10.1038/s41586-018-0691-0. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Want to better facilities for tourists Krishnendu Narayan Choudhury


first_imgWith a new dynamic tourism minister at the helm of affairs, West Bengal tourism is planning a big leap forward. The new tourism minister, Krishnendu Narayan Choudhury, on Thursday launched a major campaign in Delhi setting a tone that he means serious business. In an exclusive interview with the Millennium Post, he has described many of his new plans for the future. Read on…It is commonly perceived that West Bengal is lagging behind in promoting tourism? Also Read – ‘Playing Jojo was emotionally exhausting’It is a fact that our state earlier had not given enough importance to tourism but after the new government took over under the leadership of Mamata Banerjee, we have given a very special focus to tourism. We have the Sunderbans, Darjeeling, Deegha but enough initiative was not taken to promote such destinations. After I took over, I am focusing on improving the existing infrastructure so that we can offer better facilities to the tourists.   We are trying to do tie-ups with the industries as a whole like travel-agents, tour operators, other state governments, foreign governments and private players. Our budget allocation for tourism has also increased to Rs. 120 crores which is a big leap. We are also tied-up with Pawan Hans Helicopters Ltd to provide helicopter service facilities to different parts of Bengal particularly with tourist destinations like Sunderbans, the hills and Deegha. We are also trying to create new infrastructure for some tourist destinations like Gajaldoba which is near Bagdogra Airport and Jharkhali in Sunderban. Also Read – Leslie doing new comedy special with NetflixWhat other infrastructure developments are you planning?Through public-private partnership, we are planning to create road-side facilities for the travellers like restrooms, canteens etc. With our existing 27 tourist lodges (out of which 11 have been leased out to private companies), we are planning to improve the quality and services by professionalized management and training. Our motto is to treat every tourist as an important guest of the state. We are focusing on both, high-end as well as the budget travellers. How about foreign travelers? At present, an average of 3000 foreign travellers  come to West Bengal and our position is 6th in all India basis but we are planning to increase it to 10,000 within next three years. A lot of big hotel chains are showing interest to set up more hotels in our state for which our government is going to extend all assistance.But what about the disturbances in the hills, Darjeeling area due to agitation?After our government took over, highest number of tourists arrived in the hills after a long gap and our CM is doing everything for the development of the hills. The livelihood of the local people is totally linked with tourism and we are hopeful that peace will remain there and more tourists will visit the hills.last_img read more

A mix of music


first_imgA four-day musical event Raag Rang is being organised in the Capital that kick starts on 28 August at Central Park, Rajiv Chowk. Brought by the Department of Art and Culture, Delhi Government in association with Sahitya Kala Parishad, the festival will be a fine mix of classical, cultural and rock shows. Veteran singers and performers? like Malini Awasthi, Ahmed Hussain, Mohd. Hussain and the band Astitva will be enthralling the audience with their live renditions. Also Read – ‘Playing Jojo was emotionally exhausting’The opening day of the festival (28 August) will feature Anupriya Deotale, Ahmed Hussain and Mohd. Hussain. Ahmed and Mohammed Hussain, the two brothers, are classic ghazal singers from Jaipur. They started their singing career in 1958 as classical and thumri artistes. Their first album Guldasta was released in 1980 and since then they have released about 50 albums. Their recent release was Khwab Basera.The second day of the event (29 August)will see performances by well known sufi singer Indira Naik and the multi genre Hindi band Astitva. The band five member band was formed in 2007. They blend jazz, rock and Hindustani classic with their soulful lyrics written in Hindi and Urdu. Also Read – Leslie doing new comedy special with NetflixMalini Awasthi and Devand Jha will be taking the stage on the third day (30 August) of the event. Awasthi is the face of folk music in India and is credited in bringing back these traditional forms of music to the national stage. She is acclaimed for her gaayiki and her powerful varsatile performances. Singing the various forms of folk music from Benaras and Awadh like the Dadra, Sohar, Banna, Jhoola, Kajri, Holi, Chaiti, Vivaah, Dhobiya, Nirgun, etc. she showcased these different forms of folk music in her own way. She is one of the leading thumri singers of the Benaras Gharana. The closing day (31 August) will feature Teejan Bai and Sadhna Bhatia. Teejan Bai  is an exponent of Pandavani, a traditional performing art form, from Chhattisgarh, in which she enacts tales from the Mahabharata, with musical accompaniments. She travelled all over the world as a cultural ambassador, to countries like – England, France, Switzerland and Germany.When: 28- 31 AugustWhere: Central Park, Rajiv ChowkTiming: 6.30 pm onwardslast_img read more

MCA to decide on Ankeet letter


first_imgMCA has received a formal request from banned cricketer Ankeet Chavan to be allowed to resume his cricket career and the state association will decide on the matter at its managing committee meeting on August 2.“We have received a formal request from Chavan that he be allowed to play again. We will put it before our President Shri Sharad Pawar and other managing committee members at our meeting on Sunday,” said Mumbai Cricket Association’s joint secretary Dr P V Shetty on Wednesday. Shetty said whatever be the decision of the managing committee on the issue, the final authority is the Cricket Board. Also Read – Khel Ratna for Deepa and Bajrang, Arjuna for Jadeja“We may decide to forward his letter along with our own decision to the BCCI. But we will abide by whatever the BCCI says, “ he added. Chavan has been cleared of spot fixing charges levied by the Delhi police by a trial court. However the BCCI which had conducted it’s own enquiry on the charges relating to the 2013 edition of IPL has said that the ban would not be lifted.last_img read more

Experts to decide stability of weak Bagree Market


first_imgKolkata: The state government has decided to consult experts to assess the “strength” of the six-storeyed Bagree Market building considering that it might have turned “weak” with the devastating fire continuing to burn inside it for the past 60 hours.This comes a day after the Group of Ministers (GoM) held a meeting at Nabanna and a committee has been set up to probe the incident.Sources said that the necessity to assess the condition of the building has been felt considering two basic aspects. Firstly, it is a 55-year-old building and secondly it could have become “weak” with the recent incident of fire.It is learnt that the step to engage experts have been taken considering that the structural engineers can ascertain whether there is any need to pull down the building or any particular portion of the same. A senior official said it would lead to another disaster if any portion of the building collapses later. The structure is situated at Canning Street which is extremely narrow and congested, especially on weekdays and would claim lives if any portion of the building collapses all of a sudden. “So, as a precautionary measure, the assessment will be carried out to ensure security of the people,” the official said.The police have also been directed to find out the authorities of Bagree Estates Private Limited. An FIR was also lodged against the directors of BEPL – Radha Bagree and Varun Raj Bagree — and also against its Chief Executive Officer, Krishna Kumar Kothari.The official maintained that the report of the experts is quite crucial as subsequent steps need to be taken if they suggest to bring down the building or some of its portion.The six-storeyed Bagree Market at 71, Canning Street, where the fire broke out in the wee hours on Sunday, houses around 900 shops, godowns and offices. So the issue of rehabilitating some of the traders to some other location could also crop up if decision is taken to bring down the building or any of its portions. In that case, the state government will be extending necessary support as much as possible for the sake of the people.It may be mentioned that the devastating fire led to loss of crores of rupees. So the state government is all set to take precautionary measures to avert such incidents in future.last_img read more

Traffic goes haywire after container hits Chingrihata Flyover height guard


first_imgKolkata: Huge traffic congestion occurred on Eastern Metropolitan Bypass (E M Bypass) after a container carrier goods vehicle hit the height guard of Chingrihata Flyover on Thursday afternoon.Almost after 30 minutes, police succeeded to remove the container carrier. But till then, the tail of the congestion reached Tagore Park area on E M Bypass and above Gobinda Khatik Road on Maa Flyover.Locals said around 2:50 pm on Thursday a ten wheeler container carrier goods vehicle tried to avail Chingrihata Flyover. Though there were several signage boards and flexes put up by police saying no heavy vehicle is allowed on the Flyover — height barrier is in place. Despite the signage boards, the driver somehow failed to notice those. Also Read – Rain batters Kolkata, cripples normal lifeThe driver drove towards Chingrihata Flyover. As soon as the container carrier reached the approach road of the Flyover, it hit the height barrier at a good speed. Immediately, the height barrier came down on the vehicle damaging the driver’s cabin badly. The driver of the container carrier, Debashish Gupta, received severe mutiple injuries as a result. Police from Beliaghata Traffic Guard came and started the rescue operation.Sources informed that with the help of locals police managed to recover Gupta and admitted him to a private hospital near Kadapara. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedAccording to the police, his condition is very critical. Later almost after half an hour, the container carrier was removed from the accident spot using a heavy crane. The traffic situation remained messed up until it was moved. The Maa Flyover was packed with cars. Within 10 minutes, the traffic congestion reached Gobinda Khatik Road crossing on Maa Flyover. The North bound vehicles on E M Bypass got choked. The tail of the traffic congestion reached Tagore Park area near Ruby crossing. Sources said immediately traffic sergeants of Beliaghata and Tiljala traffic guards were deputed along E M Bypass to control the situation.It took almost two and a half hours to normalise the traffic. The vehicle has been handed over to Pragati Maidan Police Station for necessary action. Police are yet to obtain the details of the owner of the container carrier. He will be called as soon as the investigators get hold of the owner’s address and phone number.last_img read more

Amartya Sens sisters Bolpur house robbed


first_imgKolkata: The house of Kajari Roy Chaudhury, sister of Noble laureate Amartya Sen, was robbed on Tuesday night. According to the sources, the neighbours of Roy Chaudhury noticed the windows were broken and informed police.Roy Chaudhury owns a house at Gurupally in Bolpur. However, she stays in Kolkata for professional reasons. She visits there twice a year and for the rest of the year, the house remains locked. On Wednesday morning, some neighbours noticed broken window panes and immediately informed her and called the police. The sleuths found the lock of the main door broken and two almirahs were empty. They suspect more than one person’s involvement in the crime. Though a probe has been initiated, police are yet to make arrests. They are checking with sources if any local miscreant was noticed in the area recently.last_img read more

Get exclusive handcrafted creations from Northeast


first_imgIn an endeavour to promote Northeastern region’s handicraft and handloom products and the spirit of craftsmanship, CCIC presents “Purvayan”, an exhibition cum sale of exclusive Northeast products – handcrafted by master craftsperson from Northeastern states of India in its showroom at Janpath, New Delhi. The exhibition will be open to the visitors up to February 18. Timings: 10 am to 7 pm (Open all seven days including Sunday) The exhibition showcases a wide variety of handcrafted products from Northeastern regions of India ranging from bamboo handicrafts, grass handicrafts, cane handicrafts, handloom textiles and made-ups etc available in myriad shades and design from eight Northeastern states – Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura.One of the core objectives of this event is to promote products from Northeastern region of India and provide a marketing platform to the craftsperson from Northeast to present their best creations to a wider audience to increase the awareness. Another attraction of the exhibition is the live-demonstration by craftsperson.last_img read more

Siddha Group introduces Rooftop Skyplex


first_imgSiddha Group, Eastern India’s leading real estate developer, recently announced a first-of-its-kind initiative, Rooftop Skyplex, at their projects with Skywalks to give Kolkatans an altogether new movie-watching experience like never before.Siddha Group has always been a pioneer in introducing new dimensions in real estate; be it the longest ever Rooftop Skywalk in the world at an affordable residential project or the Siddha homebuying App and more. Skyplex is an additional feature where Siddha home-buyers can watch movies at the open air Rooftop Skywalks in an amphitheater setting. Also Read – Add new books to your shelfA lot of residential condominiums have introduced the concept of mini theatres at their residential clubs but Siddha Group is going a step forward and introducing Rooftop Sky Theatre experience with Skyplex with modern projection technologies with hi-tech sound system at their Skywalks. “We have always added innovations in our projects which have made home buying and living experience for the customers better. With our Rooftop Skywalks being the talk of the town, we added this extraordinary feature in the form of Skyplex in our Skywalks. Because who wouldn’t love the experience of watching their favourite movies or watching their favourite teams fight it out at the fields, at the rooftop under the sky in the open air. Now-a-days it is all about providing unique experiences and we are sure this is something our customers will look forward to”, said Sanjay Jain, Managing Director, Siddha Group. Siddha will be adding this feature across their affordable Skywalk projects that include Siddha Sky at EM Bypass, Siddha Suburbia on Southern Bypass, Siddha Eden LakeVille on BT Road and Siddha Galaxia at Rajarhat. All the Skyplex are proposed to have a 2K projection and dolby digital sound system. Comfortable sit outs across the amphitheatre will provide ample seating space for the residents.last_img read more

Forgotten History Former Slaves in the Battle of Negro Fort


first_imgThroughout the history of the struggle for freedom, slaves in America encountered many examples of brutality and methods put into place in order to preserve slavery within the country. One terrible deed was the destruction of what was then known as Negro Fort. While the War of 1812 raged on between the British and American soldiers, a fort had been built in Spanish controlled Florida for the purpose of garrisoning British troops. This fort had a considerable black population, mainly composed of escaped slaves and free men. Choctaw and Seminole tribe members also resided within the fort.The War of 1812.By 1815, the British soldiers decided to withdraw their presence from Negro Fort and move on. However, as a means of sabotaging future U.S. efforts to move into Florida, the British left the black population fully armed. This would ensure that the fortress would be able to maintain its independence from the United States, at least so they believed.Negro Fort, outside of the reach of the U.S government, quickly became a haven for slaves in America who sought to escape from their bonds.Any slave who was able to reach this territory would have true freedom. The community surrounding the fort flourished, as many slaves were quite familiar with farming methods and were able to sustain their population without problem.A plaque at the site of Negro Fort marking the location of the powder magazine.Heavily armed and autonomous, this community made many anti-abolitionists in the United States worried. Here was an example of free black men and women living well, taking care of themselves and managing their communities which could inspire more slaves to escape.This could also have potentially led to stronger arguments for abolition. Such a place was decried as dangerous and there was considerable pressure on the government to act against the fort.Andrew Jackson, then the Secretary of War, had no favorable things to say about the fort. Instead, he pushed for the Spanish government to neutralize the place. Without a reply from the Spanish, Jackson gave the order for General Edmund Gaines to destroy Negro Fort under a thinly veiled pretense.Andrew Jackson.While Negro Fort operated peacefully, the United States set up a fortress of their own nearby, as a means to ensure a secure border and most likely to provoke a diplomatic incident between the two parties.With Fort Scott placed on the Flint River, the only way supplies could reach it was to pass through the Apalachicola River, which Negro Fort controlled. One day, in 1816, two gunboats escorting supplies sailed up the Apalachicola River.Drone footage of Badbury Rings, UK in 4KGeneral Gaines had ensured that these boats, armed with artillery, would have a large enough troop escort to provoke a response from Negro Fort. No peaceful party would move such a heavily armed escort through this territory, and so the Negro Fort soldiers, they thought, would most likely act first as a means to protect themselves from invasion.General Edmund Pendleton Gaines.Sure enough, when a detachment of Gaines’ men was getting water from the river, soldiers from Negro Fort ambushed them, killing five and capturing the rest.This “unprovoked” attack would be all the justification that Andrew Jackson and Gaines would need to lay siege to the fort. Their goal was to demolish the fort and “return” the escaped slaves who they claimed to have been stolen.On July 27, 1816, Negro Fort found itself embroiled in military conflict. One of the commanders of the fort, Garcon, told emissaries that they would not surrender, no matter what. They raised the British flag high, as well as a red flag.This flag symbolized what the 330 soldiers stationed at the Fort believed in. They would fight without quarter and they would rather die than become slaves again.Map of Fort Gadsden and the Negro Fort.Thanks to British armaments, Negro Fort was too formidable for Gaines to be able to assault outright. With a great amount of gunpowder, muskets, and cannons, the black and Native American soldiers would be able to inflict many casualties in a frontal assault. Instead of a full-assault however, the order was given for the gunboats to begin their bombardments.A Union Jack on the site of the original British fort. Photo by JW 1895 CC BY SA 2.5While both sides were prepared for a heavy battle, neither expected what came next. The first of the ordinances fired from the U.S. cannons crashed into the powder magazine of the fort. This heated shot ignited the powder and created an explosion that utterly devastated the fort.Over 200 occupants of the fort died immediately, and the rest would succumb to their wounds in a short amount of time. The Battle for Negro Fort was over with one fateful shot.Read another story from us: The Colombian army hired a marketing wizard to produce a radio hit single with a hidden message, intended for hostages held in the jungleIn the end, this short conflict would quickly fade from the mind of the American public. The fort, one of the first bastions of hope and prosperity for the black community, was destroyed. But the ideals which led to its creation had only just begun to sprout.Andrew Pourciaux is a novelist hailing from sunny Sarasota, Florida, where he spends the majority of his time writing and podcasting.last_img read more

How Cats Came to be Associated with Witchcraft


first_imgToday, cats are arguably the most-loved animals on the internet, with countless memes, videos, and images devoted to these furry feline creatures. It’s hard to imagine a time when cats were not universally loved and adored.However, in Western Europe, during the Middle Ages, the humble cat was one of the first victims of the early Medieval Inquisition.In the 12th and 13th centuries, a wave of concern over the presence of witchcraft and heresy spread through the Latin West.A witch riding a broomstick with a black cat.Cats came to be seen as a symbol of witchcraft, and even as the embodiment of Satan himself.Where once these creatures had been common household animals, they were now regarded as dangerous, unpredictable and demonic.They were shunned, persecuted and often killed by people who feared that they would open the door to the devil.The Black Death of London, 1665.But how did the cat come to be so strongly associated with devil worship? According to History Collection, in the early 13th century, successive Popes began to be extremely concerned about the presence of heresy in Christian society.In 1209 Pope Innocent III preached a crusade against the Cathars of Southern France, resulting a period of intense violence and religious persecution. But the Cathars were not the only group whose practices were branded as devil worship by the Catholic Church.Pope Innocent IIIIn the early 1230s, the new Pope, Gregory IX, turned his attention north to Germany. He appointed a High Inquisitor, Conrad of Marburg, to investigate claims that groups of witches were organizing satanic rituals and threatening the sanctity of the faith.Conrad took his duties very seriously and employed brutal methods to extract confessions from would-be heretics.He reported his findings to Gregory, who was appalled at the anti-Christian beliefs and practices that had spread throughout Germany.Pope Gregory IXGregory responded by issuing a papal bull, known as Vox in Rama. This document condemned the devil-worship taking place in Germany, describing the satanic rituals and heretical practices in salacious detail.According confessions extracted from these Luciferians, new initiates to the cult were expected to kiss the behind of a toad before paying homage to a black cat, which they were also expected to kiss.At the end of the ritual, a strange half-man, half cat appeared, taken to be the embodiment of the devil himself.Satan Exulting Over Eve by William Blake. The subject of the bull deals with the devil and his corruption of innocents through fornication.According to History Collection, Vox in Rama firmly established the association between cats and the devil in Christian culture.However, the description of the devil as a black cat tapped into already deep-seated cultural beliefs about the nature and symbolic significance of cats in pagan religions.Could this cute black kitten really be in cahoots with the devil?The Egyptian goddess Bast was represented by a cat, as was the Greek goddess of the underworld, Hecate.The strong presence of cats in pre-Christian religions positioned them as antithetical to Christian belief. In addition, cats were often described as cruel, vindictive creatures that could not be tamed like other domestic animals.The Gayer-Anderson cat, believed to be a representation of Bastet. Photo by Einsamer Schütze CC BY-SA 3.0They were observed playing with their prey, torturing mice before finally finishing them off, and this fed the popular belief that they were unpredictable and wicked.According to historian Irina Metzler, cats were already regarded as inherently linked to heresy, wildness and anti-Christian beliefs.A 19th century drawing of a tabby cat.This may have also been due to the acceptance of cats in Islamic societies. Medieval Muslims admired cats for their cleanliness and they had been well treated by the Prophet Muhammad.This may have contributed to the notion that cats existed outside the Christian social order. In the late 12th century, many people began to believe that killing or torturing a black cat was a good method to break spells and curses.Casting call for black cats, Los Angeles, 1961. The studio was seeking cats for the Roger Corman movie Tales of Terror.The widespread cat massacres that followed Vox in Rama have also been suggested as an indirect cause of the Black Death, the plague that spread through Europe in the 14th century.The lack of cats led to an increase in rats and mice, which were alleged to have spread the plague.However, this argument is insufficient to account for the Black Death, which was spread by fleas that could have been carried on any humans or animals. Although the cat population diminished radically, they were not completely wiped out.Read another story from us: Amazingly Well-Preserved Ice Age Horse Discovered in Siberian PermafrostThe heresy trials that accompanied the promulgation of the Vox in Rama was a frightening precursor to the Inquisition, in which tens of thousands of people were put to death. The massacre of cats in the early 13th century was simply the beginning of a very dark and terrifying period in Christian history.last_img read more

Henry VIII Letter that Reflected War Preparations in 1541 Auctioned


first_imgA letter from King Henry VIII appointing a master gunner to the royal garrison in Hull, believed to have been written in 1541, was auctioned for $25,000 (£20,000). The note is signed “Henry R” and bears the remains of a wax seal. It was sent to Sir Richard Long and Michael Stanhope, the commanders of the city’s military base.The King asked that the gunner, Thomas King, be paid wages of eight pence a day, with four pence for his assistant.Portrait of Henry VIII, c. 1536. Oil and tempera on oak, Thyssen-Bornemisza Museum, Madrid.Henry VIII traveled to the north of England in 1541 with his fifth wife, Catherine Howard. One of his goals was to meet James V of Scotland, the son of his older sister, Margaret. James V did not show up, however.Henry visited Hull as part of this royal progress. The auctioneers said: “Henry visited Hull in August and September 1541 and made extensive orders for its fortification and garrisoning over the following months, perhaps in preparation for his attack on Scotland later in 1542.”There were other tensions to be dealt with besides Scotland.The letter was sent to the commanders of Hull’s military garrison.In mid-September 1541 Henry VIII, his wife, and his courtiers entered the city of York. There the mayor, aldermen, and other leaders begged for forgiveness from Henry VIII for their participation in an earlier religious rebellion called the Pilgrimage of Grace.The Pilgrimage of Grace was a widespread rebellion across the north prompted by distress over Henry VIII’s break with the Catholic Church and his Dissolution of the Monasteries. The king ransacked the abbeys, and the monks, nuns, and friars were rendered homeless.Photo by HFAThe disruption to the kingdom was made stark in an archaeological dig conducted at Hull.  According to the BBC, “archaeologists at the Hull excavation found stones taken from destroyed monasteries which were reused in some of the walls at the fort.”Henry VIII had ordered that Hull’s defenses be strengthened. A stone block house was built in 1541 at a cost of more than £20,000 to house guns and to protect the gunners and ammunition.Portrait of Henry VIIIIt was part of a system of three forts linked by a curtain wall intended to protect the city and its port.The fact that Henry VIII was personally ordering payments for people in this letter also bears testament to the King personally overseeing many matters in his country after the execution of Thomas Cromwell in July 1540. For a number of years before his arrest for treason, Cromwell administered the business of England for Henry.Thomas Cromwell by Hans Holbein the Younger (1532/1533).Cromwell was executed the same day that Henry VIII married Catherine Howard, who was perhaps 17 years old. But while Henry was able to control the payment of the gunner for the Hull fortifications, it turned out he could not control his young wife.While Queen Catherine accompanied Henry VIII on his progress through the north, she was secretly meeting with a young courtier named Thomas Culpepper.Catherine of Aragon, Henry’s first queen.When the royal couple returned to England, Henry was given a letter by the Archbishop of Canterbury saying that his wife had had a “dissolute” life before marrying him.His beautiful young queen was eventually arrested for adultery, as were Culpepper and a man she had a relationship with before becoming queen, Francis Dereham.Henry VIII wept when told of the reports of his wife’s infidelity. He did not grant her mercy, however. She was beheaded on February 13, 1542 at the Tower of London.That same year, England went to war with Scotland. James V led an army south but he was defeated in the Battle of Solway Moss, even though the Scottish forces outnumbered the English.Read another story from us: A Closer Look at the Incredibly Bizarre Horned Helmet of Henry VIIIHumiliated, depressed, and ill, James V died on December 14, 1542. He was succeeded by his infant daughter, who became known as Mary, Queen of Scots.As for Henry VIII, he married one more time — the widow Catherine Parr — before dying in 1547.Nancy Bilyeau, a former staff editor at Entertainment Weekly, Rolling Stone, and InStyle, has written a trilogy of historical thrillers for Touchstone Books. Her new book, The Blue, is a spy story set in the 18th-century porcelain world. For more information, go to www.nancybilyeau.comlast_img read more

Musical Twist Jimi Hendrix and Joe Pesci Once Played in the Same


first_imgBefore they became a famous actor and rock star respectively, Joe Pesci and Jimi Hendrix were in a house band called Joey Dee and the Starliters. They played at a venue called The Peppermint Lounge in Manhattan. Led by Dee on vocals, their song Peppermint Twist (Part 1) hit the top spot in 1962. Hendrix (then known as Jimmy James) didn’t join the group till later but Pesci was strumming along for the ride. Both were young men, just entering their 20s.Hendrix on stage in 1967Peppermint Twist drew on the Twist dance craze, described on Dee’s website as “the liberation of the dance floor,” which excited teenagers and started “a media thunderstorm.”“Doctors warned of back injuries, religious figures cluck-clucked over the moral implications, and dancers such as Fred Astaire looked down their nose at the vulgarity of it all.”AdChoices广告inRead invented by TeadsJoey and the Twisters performing at the Peppermint Lounge in Manhattan, c. 1962Chubby Checker’s legendary track announced the dance to the world, but The Peppermint Lounge is credited with turning it into a national pastime. It was “the Studio 54 of its day” according to a 2018 Stereogum article. Celebrities could be seen sipping drinks and twisting the night away, including Marilyn Monroe, John Wayne, Truman Capote and Judy Garland.Pesci and Hendrix were just passing through in the overall scheme of things. Nevertheless, they were part of something big. The Peppermint Twist’s status as a hall of famer is disputed, with Stereogum saying it was “a song made for a very specific cultural context, and once that context disappeared, so, for the most part, did the song.”Joey Dee, 1962However, Dee believes the result was more than worthwhile. In an interview for the Classic Bands site he commented, “The Peppermint Lounge without the publicity would not have engendered The Peppermint Twist, and without The Peppermint Twist I don’t think the Peppermint Lounge would have had the longevity it achieved.”Hendrix kept playing the guitar and when things went electric he turned into a phenomenon of his own. “I had him come out to my garage and audition. After the first five minutes I knew he was the guy for my band,” said Dee. “He was a wonderful team player, a fine guitarist, similar to Curtis Mayfield… I have nothing but good thoughts about Jimi.”The Experience in 1968Pesci moved into acting, something he’d been urged to do by his father Angelo. In interviews, he has mentioned it not being his choice. Having trod the boards since childhood, his interest ran out in the mid-Seventies after he failed to crack Hollywood.Luckily he’d made a low budget crime flick in 1976 which caught the attention of Scorcese. He was working as a restaurant manager when Robert De Niro and Martin Scorsese got in touch. They wanted to cast him in Raging Bull (1980) based on his performance. Noisey referred to him as “the Shakespeare of unrelenting anger.” Pesci built a reputation for inhabiting mercurial personalities, most notably Tommy DeVito in Goodfellas (1990), though he is also a respected character actor who played comedy and drama.The Starliters certainly weren’t the be and end all of Pesci’s journey as a recording artist. The former lounge singer has always had music in his blood — to date he’s released two albums, 1968’s Little Joe Sure Can Sing! and Vincent LaGuardia Gambini Sings Just for You in 1998, named after his character from My Cousin Vinny (1992).Joe Pesci in a promotional photo for Scorcese’s ‘Goodfellas’. Photo by Getty ImagesThe latter release featured a hilarious rap track titled “Wise Guy”, which was critically-derided. Noisey said, “the essence of the track and video shines through the fog like a pair of nauseatingly well-lit headlights.” Though he has been praised for his musical talent, this was seen as a misstep.Before his break from acting in 1999, he won the Academy Award for Best Supporting Actor (for Goodfellas). Lethal Weapon’s fast-talking Leo Getz and Home Alone’s burglar Harry Lyme were his most popular roles. He is about to be seen in Scorsese’s The Irishman.Read another story from us: Final Days of Jimi Hendrix – Theories Surrounding the Early Demise of a Rock LegendThey went on to entertain in their own unique ways. But for a heady period in the Sixties, Joe Pesci and Jimi Hendrix were at the epicenter of a great American cultural revolution.last_img read more