High pressure and small spaces create order from disorder
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nother approach to address perovskites’ thermal stability is to use inorganic perovskites such as CsPbX3, where the cesium (Cs) cation is less volatile. There has been growing interest in perovskites for light-emitting field-effect transistors and phototransistors. By integrating organic and inorganic cations, a research
team has made a triple cation perovskite Csx(MA0.17FA0.83)1–xPb(Br0.17I0.83)3 that has low amounts of electronic defects and better thermally stability. Mohammad Khaja Nazeeruddin of the École Polytechnique Fédérale de Lausanne, Switzerland, Jin Jang of Kyung Hee University in South Korea, and their
colleagues used the new material to make field-effect transistors that have mobilities over 2 cm2/V-s and inverters with voltage gains over 20. The researchers say that these are the best reported performances of such perovskite devices. The work is reported in Advanced Materials (doi:10.1002/adma.201602940).
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cation (C4N2H142+) to form core–shell wires. Millions of these wires are stacked together to form a crystalline bundle. The 1D structure is excellent at trapping electron–hole pairs called excitons. This leads to efficient bluish white-light emissions with photoluminescence quantum efficiencies
of approximately 20% for the bulk single crystals and 12% for the microscale crystals, as reported in Nature Communications (doi:10.1038/ncomms 14051). The material could open up a new way to make efficient light-emitting devices and phosphor materials for display applications.
esearchers at Florida State University have made a new organic–inorganic metal halide perovsite with a one-dimensional (1D) structure. The material has a 1D perovskite structure where the edge-sharing octahedral lead bromide chains [PbBr4–2]n are surrounded by columnar cages formed by an organic
High pressure and small spaces create order from disorder
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eologists have long studied the effects of high pressure on water in the porous media of rocks and minerals in the earth’s crust, mainly to explore deformation properties. Now Gloria Tabacchi, a computational chemist at the University of Insubria, Italy, has enlisted the help of her earth science colleagues to study the effects of high pressure on an ethanol/water solution in the channels of a zeolite. The result is a new material that separates ethanol dimers in one channel of the zeolite and water tetramers in another channel. Perhaps most significantly, the material maintains its structure when the pressure is removed, opening up the possibility of room temperature, ambient pressure devices that could separate more complex molecules for various applications, such as solar energy conversion. “Usually, when you create something under pressure, all the interesting properties disappear when you release the pressure,” Tabacchi says. “So this was a very nice surprise.” In this proof-of-principle research published in a recent issue of Angewandte Chemie (doi:10.1002/anie.201610949), the investigators chose a simple ethanol/ water solution because it was easier to
study expe
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