A perovskite is any material with the same type of crystal structure as calcium titanium oxide (CaTiO 3 ), known as the perovskite structure , or XII A 2 + VI B 4+ X 2- 3 with the oxygen in the face centers .  Perovskites take their name from the mineral , which was first discovered in the Ural mountains of Russia by Gustav Rose in 1839 and is named after Russian mineralogist LA Perovski(1792-1856). The general chemical formula for perovskite compounds is ABX 3 , where ‘A’ and ‘B’ are two cations of very different sizes, and X is anion that bonds to both. The ‘A’ atoms are larger than the ‘B’ atoms. The ideal cubic-symmetry structure has the B cation in 6-fold coordination, surrounded by an octahedron of anions , and the cation in 12-fold cuboctahedral coordination. The invention relates to the stability of the outer space, the effects of which can be reduced, and the presence of several lower-symmetry distorted versions, in which the coordination numbers of A cations, B cations or both are reduced.
Natural compounds with this structure are perovskite , loparite , and silicate perovskite bridgmanite.  
The perovskite structure is adopted by many oxides that have the chemical formula ABO 3 .
In the idealized cubic unit cell of such a compound, type ‘B’ atom sits at cube corner positions (0, 0, 0), type ‘A’ atom sits at body center position (1/2, 1/2, 1 / 2) and oxygen atoms sit at face centred positions (1/2, 1/2, 0). (The diagram shows edges for an equivalent unit cell with A in body center, B at the corners, and O in mid-edge).
The invention relates to the stability of the outer space, the effects of which can be reduced, and the presence of several lower-symmetry distorted versions, in which the coordination numbers of A cations, B cations or both are reduced. Tilting of the BO 6 octahedra reduces the co-ordination of an undersize. A cation of 12 to as low as 8. Conversely, an off-centering of an undersize The resulting electric dipole is responsible for the property of ferroelectricity and shown by perovskites such as BaTiO 3 that distort in this fashion.
The orthorhombic and tetragonal phases are most common non-cubic variants.
Complex perovskite structures contain two different B-site cations. This results in the possibility of ordered and disordered variants.
The most common mineral in the earth is bridgmanite, a magnesium-rich silicate which adopts the perovskite structure at high pressure. As pressure increases, the SiO 4 4- tetrahedral units in the dominant silica-bearing minerals become unstable compared with SiO 6 8- octahedral units. The most abundant material is a perovskite-structured mineral with the formula (Mg, Fe) SiO 3 , with the second most abundant material likely to rocksalt-structured (Mg, Fe) O oxide , periclase . 
At the high pressure conditions of the Earth’s lower mantle , the pyroxene enstatite , MgSiO 3 , transforms into a perovskite-structured polymorphic denser ; This phase may be the most common mineral in the Earth.  This phase has the orthorhombically distorted perovskite structure (GdFeO 3 -type structure) that is stable at pressures from ~ 24 GPa to ~ 110 GPa. However, it can not be transported from depths of several hundred kilometers to the Earth’s surface without transforming back into less dense materials. At higher pressures, MgSiO 3 perovskite transforms to post-perovskite .
Although the most common perovskite compounds contain oxygen, there are a few perovskite compounds that form without oxygen. Fluoride perovskites such as NaMgF 3 are known. A large family of metallic perovskite compounds can be represented by RT 3 M (R: rare-earth or other relatively large ion, T: metal ion transition and M: light metalloids). The metalloids occupy the octahedrally coordinated “B” sites in these compounds. RPd 3 B, RRh 3 B and CeRu 3 These are examples. MgCNi 3 is a metallic perovskite compound and has received a lot of attention because of its superconducting properties. An even more exotic type of perovskite is represented by the mixed oxide-aurides of Cs and Rb, such as Cs3 AuO, which contains large alkali cations in the traditional “anion” sites, bonded to O 2- and Au – anions.
Perovskite materials exhibit many interesting and intriguing properties from both the theoretical and the application point of view. Colossal magnetoresistance , ferroelectricity , superconductivity , charge ordering , spin dependent transport, high thermopower and the interplay of structural, magnetic and transport properties. These compounds are used as catalysts and catalysts in certain types of fuel cells  and are candidates for devices and spintronicsapplications. 
Many superconducting ceramic materials (the high temperature superconductors ) have perovskite-like structures, often with 3 vacancies. One prime example is yttrium barium copper oxide which may be insulating or superconducting depending on the oxygen content.
Chemical engineers are considering a cobalt-based perovskite material as a replacement for platinum in catalytic converters in diesel vehicles. 
Physical properties of interest to materials science Among perovskites include superconductivity , magnetoresistance , Ionic conductivity , and a multitude of dielectric properties, qui are of great importance in microelectronics and telecommunication . Because of the flexibility of bonds angles inherent in the perovskite structure there are many different types of distortions which can occur from the ideal structure. These include tilting of the octahedra , displacements of the cations out of the centers of their polyhedra coordination, and distortions of the octahedra driven by electronic factors ( Jahn-Teller distortions ).
Synthetic perovskites have been identified as possible inexpensive base materials for high-efficiency commercial photovoltaics   – they showed a conversion efficiency of up to 15%   and can be manufactured using the same thin-film manufacturing as used for thin film silicon solar cells.  Methylammonium tin halides and methylammonium lead halides are of interest for use in dye-sensitized solar cells .   In 2016, power conversion efficiency reached 21%. [ quote needed ]In July 2016, a team of researchers led by Dr. Alexander Weber-Bargioni showed that perovskite PV cells could reach a theoretical peak efficiency of 31%. 
Among the methylammonium halides, the most common is methylammonium lead triiodide ( CH
3 ). It has a high load carrier mobility and load carrier lifetime that allow light-generated electrons and holes to move far away from the current world. CH
3 effective diffusion are some 100 nm for both electrons and holes. 
Methylammonium halides are deposited by low-temperature solution methods (typically spin-coating ). Other low-temperature (below 100 ° C) solution-processed films tend to have smaller distribution smaller diffusion lengths. Stranks et al. Described nanostructured cells using a mixed halide lead methylammonium (CH 3 NH 3 PbI 3-x Cl x ) and Demonstrated one amorphous thin film solar cell with an 11.4% conversion efficiency, and Another That Reached 15.4% using vacuum evaporation. The film thickness of about 500 to 600 nm implies that the electron and hole diffusion lengths were at least of this order. They measured values of the diffusion length exceeding 1 μm for the mixed perovskite, an order of magnitude greater than 100 nm for the pure iodide. They are shown to be in the mixed perovskite are longer than in pure iodide. 
3 , open-circuit voltage (V OC ) typically approaches 1 V, while for CH
3 PbI (I, Cl)
3 with low Cl content, V OC > 1.1 V has been reported. Because the band gaps (E g ) of Both are 1.55 eV, V OC -to-E g ratios are Higher Than usually Observed for similar third-generation solar cells. With greater bandgap perovskites, V OC up to 1.3 V has been demonstrated. 
The technique offers the potential of low cost because of the low temperature solution methods and the absence of rare elements. Cell durability is currently insufficient for commercial use. 
Planar heterojunction perovskite solar cells can be manufactured using simplified device architectures (without complex nanostructures) using only vapor deposition. This technique produces 15% solar-to-electrical power conversion as measured under simulated full sunlight. 
Also in 2008 the researchers showed that perovskite can generate laser light. LaAlO 3 doped with neodymium gave laser emission at 1080 nm.  In 2014 it was shown that mixed methylammonium lead halide (CH 3 NH 3 PbI 3-x Cl x ) cells optically pumped into vertical-cavity surface-emitting lasers (VCSELs) convert visible light to near-IR laser light pump with a 70% efficiency.  
Light Emitting Diodes
Due to their high photoluminescence quantum efficiencies , perovskites may be good candidates for use in light-emitting diodes (LEDs).  However, the propensity for radiative recombination has largely been observed at liquid nitrogen temperatures.
In September 2014, researchers of EPFL in Lausanne, Switzerland reported effective water electrolysis at 12.3% efficiency in a highly efficient and low-cost water-splitting cell using perovskite photovoltaics.  
- Diamond anvil
- Goldschmidt tolerance factor
- Ruddlesden-Popper phase
Examples of perovskites
- Strontium titanate
- Calcium titanate
- Lead titanate
- Bismuth ferrite
- Lanthanum ytterbium oxide
- Silicate perovskite
- Lanthanum manganite
- yttrium aluminum perovskite (YAP) 
- Lanthanum strontium manganite
- LSAT (lanthanum aluminate – strontium aluminum tantalate)
- Lead scandium tantalate
- Lead zirconate titanate
- Jump up^ A. Navrotsky (1998). “Energetics and Crystal Chemical Systematics among Ilmenite, Lithium Niobate, and Perovskite Structures”. Chem. Mater. 10 (10): 2787. doi : 10.1021 / cm9801901 .
- ^ Jump up to:a b c Wenk, Hans-Rudolf; Bulakh, Andrei (2004). Minerals: Their Constitution and Origin . New York, NY: Cambridge University Press. ISBN 978-0-521-52958-7 .
- Jump up^ Bridgemanite on Mindat.org
- Jump up^ John Lloyd ; John Mitchinson . “What’s the commonest material in the world”. QI : The Book of General Ignorance . Faber & Faber. ISBN 0-571-23368-6 .
- Jump up^ Kulkarni, A; FT Ciacchi; S Giddey; C Munnings; et al. (2012). “Mixed ionic electronic conduction perovskite anode for direct carbon fuel cells”. International Journal of Hydrogen Energy . 37 (24): 19092-19102. doi :10.1016 / j.ijhydene.2012.09.141 .
- Jump up^ JMD Coey; M. Viret; S. von Molnar (1999). “Mixed-valence manganites”. Advances in Physics . 48 (2): 167-293. Bibcode : 1999AdPhy..48..167C. doi : 10.1080 / 000187399243455 .
- Jump up^ Alexandra Witze (2010). “Building a cheaper catalyst” . Science News Web Edition .
- Jump up^ Lufaso, Michael W .; Woodward, Patrick M. (2004). “Jahn-Teller distortions, cation ordering and octahedral tilting in perovskites”. Acta Crystallographica Section B . 60 : 10. doi : 10.1107 / S0108768103026661 .
- Jump up^ Eames, Christopher; Frost, Jarvist M .; Barnes, Piers RF; O’Regan, Brian C .; Walsh, Aron; Islam, M. Saiful (2015). “Ionic transport in hybrid lead iodide perovskite solar cells” . Nature Communications . 6 : 7497.Bibcode : 2015NatCo … 6E7497E . doi : 10.1038 / ncomms8497 . PMC 4491179 . PMID 26105623 .
- Jump up^ Bullis, Kevin (8 August 2013). “A Material That Could Make Solar Power” Dirt Cheap ” ” . MIT Technology Review . Retrieved 8 August2013 .
- ^ Jump up to:a b Li, Hangqian. (2016). “A modified sequential deposition method for the manufacture of perovskite solar cells” . Solar Energy . 126 : 243-251. Bibcode : 2016SoEn..126..243L . doi : 10.1016 / j.solener.2015.12.045 .
- Jump up^ Cartwright, Jon (11 September 2013). “A Flat-Out Major Advance for an Emerging Solar Cell Technology” . Science (newspaper) .
- Jump up^ Liu, Mingzhen; Johnston, Michael B .; Snaith, Henry J. (2013). “Efficient planar heterojunction perovskite solar cells by vapor deposition”. Nature . 501 (7467): 395-8. Bibcode : 2013Natur.501..395L . doi : 10.1038 / nature12509 . PMID 24025775 .
- Jump up^ Lotsch, BV (2014). “New Light on an Old Story: Perovskites Go Solar”. Angew. Chem. Int. Ed . 53 (3): 635-637. doi : 10.1002 / anie.201309368 .
- Jump up^ Service, R. (2013). “Turning Up the Light” . Science . 342 (6160): 794-797. doi : 10.1126 / science.342.6160.794 .
- Jump up^ http://factor-tech.com/green-energy/23404-nanoscale-discovery-could-push-perovskite-solar-cells-to-31-efficency/
- ^ Jump up to:a b c d Hodes, G. (2013). “Perovskite-Based Solar Cells”. Science . 342(6156): 317-318. Bibcode : 2013Sci … 342..317H . doi : 10.1126 / science.1245473 . PMID 24136955 .
- Jump up^ Liu, M .; Johnston, MB; Snaith, HJ (2013). “Efficient planar heterojunction perovskite solar cells by vapor deposition”. Nature . 501(7467): 395-8. Bibcode : 2013Natur.501..395L . doi : 10.1038 / nature12509 . PMID 24025775 .
- Jump up^ Dereń, PJ; Bednarkiewicz, A .; Goldner, Ph .; Guillot-Noël, O. (2008). “Laser action in LaAlO 3 : Nd 3+ single crystal”. Journal of Applied Physics. 103 (4): 043102. Bibcode : 2008JAP … 103d3102D . doi : 10.1063 / 1.2842399 .
- Jump up^ Wallace, John (28 March 2014)High-efficiency perovskite photovoltaic material also lases. LaserFocusWorld
- Jump up^ “Study: Perovskite solar cells can double as lasers” . Rdmag.com. 2014-03-28 . Retrieved 2014-08-24 .
- Jump up^ Stranks, Samuel D .; Snaith, Henry J. (2015-05-01). “Metal-halide perovskites for photovoltaic and light-emitting devices” . Nature Nanotechnology . 10 (5): 391-402. Bibcode : 2015NatNa..10..391S . doi: 10.1038 / nnano.2015.90 . ISSN 1748-3387 .
- Jump up^ Jingshan Luo; et al. (September 26, 2014). “Water photolysis at 12.3% efficiency via perovskite photovoltaics and Earth-abundant catalysts”. Science . 345 (6204): 1593-1596. Bibcode : 2014Sci … 345.1593L . doi: 10.1126 / science.1258307 . PMID 25258076 .
- Jump up^ “Harvesting hydrogen fuel from the Sun using Earth-abundant materials” . Phys.org. Sep 25, 2014 . Retrieved 26 September 2014 .
- Jump up^ “Yttrium Orthoaluminate – YALO3 | Scientific Materials Corporation | Yttrium Aluminum Perovskite – YAP Laser Materials” . www.scientificmaterials.com . Retrieved 2017-07-06 .