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Methylammonium lead halides (MALHs) are solid compounds with perovskite structure and a chemical formula of [CH 3 NH 3] + Pb 2+ (X −) 3, where X = Cl, Br or I. They have potential applications in solar cells , [ 2 ] lasers , light-emitting diodes , photodetectors , radiation detectors, [ 3 ] [ 4 ] scintillator , [ 5 ] magneto-optical data ...
Ternary cesium lead halides have multiple stable phases that can be formed; these include CsPbX 3 (perovskite), Cs 4 PbX 6 (so called "zero-dimensional" phase due to disconnected [PbX 6] 4-octahedra), and CsPb 2 X 5. [147] All three phases have been prepared colloidally either by a direct synthesis or via nanocrystal transformations. [148]
Crystal structure of CH 3 NH 3 PbX 3 perovskites (X=I, Br and/or Cl). The methylammonium cation (CH 3 NH 3 +) is surrounded by PbX 6 octahedra. [13]The name "perovskite solar cell" is derived from the ABX 3 crystal structure of the absorber materials, referred to as perovskite structure, where A and B are cations and X is an anion.
Perovskite (pronunciation: / p ə ˈ r ɒ v s k aɪ t /) is a calcium titanium oxide mineral composed of calcium titanate (chemical formula Ca Ti O 3).Its name is also applied to the class of compounds which have the same type of crystal structure as CaTiO 3, known as the perovskite structure, which has a general chemical formula A 2+ B 4+ (X 2−) 3. [6]
They may also include density functional theory (DFT), molecular mechanics or semi-empirical quantum chemistry methods. The programs include both open source and commercial software. Most of them are large, often containing several separate programs, and have been developed over many years.
The basic methodology is density functional theory (DFT), but the code also allows use of post-DFT corrections such as hybrid functionals mixing DFT and Hartree–Fock exchange (e.g. HSE, [3] PBE0 [4] or B3LYP [5]), many-body perturbation theory (the GW method [6]) and dynamical electronic correlations within the random phase approximation (RPA ...
[4] Exchange rates usually follow the trend I > Br > Cl. Alkyl- and arylfluoride are generally unreactive toward organolithium reagents. Lithium–halogen exchange is kinetically controlled, and the rate of exchange is primarily influenced by the stabilities of the carbanion intermediates (sp > sp 2 > sp 3) of the organolithium reagents. [5] [3]
Lead halide refers to any of a group of chemical compounds in which lead is joined to an element from the halide group. Compounds within this group include: