Photoconductivity is an optical and electrical phenomenon in which a material becomes more electrically conductive due to the absorption of electromagnetic radiation such as visible light, ultraviolet light, infrared light, or gamma radiation.
A perovskite is any material with a crystal structure following the formula ABX3, which was first discovered as the mineral called perovskite, which consists of calcium titanium oxide (CaTiO3). The mineral was first discovered in the Ural mountains of Russia by Gustav Rose in 1839 and named after Russian mineralogist L. A. Perovski (1792–1856). 'A' and 'B' are two positively charged ions (i.e. cations), often of very different sizes, and X is a negatively charged ion (an anion, frequently oxide) that bonds to both cations. The 'A' atoms are generally larger than the 'B' atoms. The ideal cubic structure has the B cation in 6-fold coordination, surrounded by an octahedron of anions, and the A cation in 12-fold cuboctahedral coordination. Additional perovskite forms may exist where either/both the A and B sites have a configuration of A1x-1A2x and/or B1y-1B2y and the X may deviate from the ideal coordination configuration as ions within the A and B sites undergo changes in their oxidation states.
A nanoring is a cyclic nanostructure with a thickness small enough to be on the nanoscale. Note that this definition allows the diameter of the ring to be larger than the nanoscale. Nanorings are a relatively recent development within the realm of nanoscience; the first peer-reviewed journal article mentioning these nanostructures came from researchers at the Institute of Physics and Center for Condensed Matter Physics in Beijing who synthesized nanorings made of gallium nitride in 2001. Zinc oxide, a compound very commonly used in nanostructures, was first synthesized into nanorings by researchers at Georgia Institute of Technology in 2004, and several other common nanostructure compounds have been synthesized into nanorings since. More recently, carbon-based nanorings have been synthesized from cyclo-para-phenylenes as well as porphyrins.
Piezochromism, from the Greek piezô "to squeeze, to press" and chromos "color", describes the tendency of certain materials to change color with the application of pressure. This effect is closely related to the electronic band gap change, which can be found in plastics, semiconductors and hydrocarbons. One simple molecule displaying this property is 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile, also known as ROY owing to its red, orange and yellow crystalline forms. Individual yellow and pale orange versions transform reversibly to red at high pressure.
A definition in semiconductor physics, carrier lifetime is defined as the average time it takes for a minority carrier to recombine. The process through which this is done is typically known as minority carrier recombination.
Harry Laurence Anderson is a British chemist in the Department of Chemistry, University of Oxford. He is well known for his contributions in the syntheses of supramolecular systems, exploration of the extraordinary physical properties of large pi-conjugated systems, and synthesis of cyclo[18]carbon. He is a Professor of Chemistry at Keble College, Oxford.
A perovskite solar cell (PSC) is a type of solar cell that includes a perovskite-structured compound, most commonly a hybrid organic–inorganic lead or tin halide-based material as the light-harvesting active layer. Perovskite materials, such as methylammonium lead halides and all-inorganic cesium lead halide, are cheap to produce and simple to manufacture.
Henry James Snaith is a professor in physics in the Clarendon Laboratory at the University of Oxford. Research from his group has led to the creation of a new research field, based on halide perovskites for use as solar absorbers. Many individuals who were PhD students and postdoctoral researchers in Snaith's group have now established research groups, independent research portfolios and commercial enterprises. He co-founded Oxford Photovoltaics in 2010 to commercialise perovskite based tandem solar cells.
Methylammonium lead halides (MALHs) are solid compounds with perovskite structure and a chemical formula of [CH3NH3]+Pb2+(X−)3, where X = Cl, Br or I. They have potential applications in solar cells, lasers, light-emitting diodes, photodetectors, radiation detectors, scintillator, magneto-optical data storage and hydrogen production.
Tsutomu Miyasaka, is a Japanese engineer in electrochemistry best known as the inventor of the perovskite solar cell.
Oxford Photovoltaics Limited is an Oxford University spin-off company in the field of perovskite photovoltaics and solar cells.
David S. Ginger is an American physical chemist. He is the B. Seymour Rabinovitch Endowed Professor of Chemistry at the University of Washington. He is also a Washington Research Foundation distinguished scholar, and chief scientist of the University of Washington Clean Energy Institute. In 2018, he was elected to the Washington State Academy of Sciences for his work on the microscopic investigation of materials for thin-film semiconductors. He was elected a member of the American Association for the Advancement of Science in 2012, and was a 2016 National Finalist of the Blavatnik Awards for Young Scientists.
Light harvesting materials harvest solar energy that can then be converted into chemical energy through photochemical processes. Synthetic light harvesting materials are inspired by photosynthetic biological systems such as light harvesting complexes and pigments that are present in plants and some photosynthetic bacteria. The dynamic and efficient antenna complexes that are present in photosynthetic organisms has inspired the design of synthetic light harvesting materials that mimic light harvesting machinery in biological systems. Examples of synthetic light harvesting materials are dendrimers, porphyrin arrays and assemblies, organic gels, biosynthetic and synthetic peptides, organic-inorganic hybrid materials, and semiconductor materials. Synthetic and biosynthetic light harvesting materials have applications in photovoltaics, photocatalysis, and photopolymerization.
Maksym V. Kovalenko is a full professor of inorganic chemistry and the head of the Functional Inorganic Materials group at ETH Zurich. A part of the research activities of the group are conducted at Empa (Dübendorf). He is working in the fields of solid-state chemistry, quantum dots and other nanomaterials, surface chemistry, self-assembly, optical spectroscopy, optoelectronics and energy storage.
Perovskite nanocrystals are a class of semiconductor nanocrystals, which exhibit unique characteristics that separate them from traditional quantum dots. Perovskite nanocrystals have an ABX3 composition where A = cesium, methylammonium (MA), or formamidinium (FA); B = lead or tin; and X = chloride, bromide, or iodide.
Hemamala Indivari Karunadasa is an assistant professor of chemistry at Stanford University. She works on hybrid organic – inorganic materials, such as perovskites, for clean energy and large area lighting.
Methylammonium tin halides are solid compounds with perovskite structure and a chemical formula of CH3NH3SnX3, where X = I, Br or Cl. They are promising lead-free alternatives to lead perovskites as photoactive semiconductor materials. Tin-based perovskites have shown excellent mobility in transistors which gives them an opportunity to be explored more for solar cell applications.
Efrat Lifshitz is an Israeli chemist at the Schulich Faculty of Chemistry and the Solid-State Institute, Technion – Israel Institute of Technology (Technion-IIT). Lifshitz's research is known for pioneering advances in developing and studying low-dimensional semiconductors by exploring the relationship between their optical properties and magnetism.
Annamaria Petrozza is an American chemist who is a professor at the Istituto Italiano di Tecnologia. Her research considers sustainable materials for optoelectronic devices. She was awarded the 2022 Materials Research Society Award in Innovation in Materials Characterization.
Samuel David Stranks is a Professor of Optoelectronics in the Department of Chemical Engineering and Biotechnology at the University of Cambridge and a Fellow of Clare College, Cambridge.
