Organometal halide perovskites have been intensely studied in the past 5 years, inspired by their certified high photovoltaic power conversion efficiency. Some of these materials are room-temperature ferroelectrics. The presence of switchable ferroelectric domains in methylammonium lead triiodide, CH3NH3PbI3, has recently been observed via piezoresponse force microscopy. Here, we focus on the s...

Organic-inorganic hybrid perovskites have the potential to be used as a new class of emitters with tunable emission, high color purity and good ease of fabrication. Recent studies have so far been focused on three-dimensional (3D) perovskites, such as CH3NH3PbBr3 and CH3NH3PbI3 for green and infrared emission. Here, we explore a new series of hybrid perovskite emitters with a general formula of...

The Raman spectra of seven A(2)MWO(6) tungstate double perovskites are analysed. Ba(2)MgWO(6) is a cubic double perovskite with Fm3[combining macron]m symmetry and its Raman spectrum contain three modes that can be assigned in a straightforward manner. A fourth mode, the asymmetric stretch of the [WO(6)](6-) octahedron, is too weak to be observed. The symmetry of Ba(2)CaWO(6) is lowered to tetr...

In this work supervised self-organizing maps were used for structural classification of perovskites. For this purpose, structural data for total number of 286 perovskites, belonging to ABO3 and/or A2BB'O6 types, were collected from literature: 130 of these are cubic, 85 orthorhombic and 71 monoclinic. For classification purposes, the effective ionic radii of the cations, electronegativities of ...

Organic-inorganic methylammonium lead halide perovskites have recently attracted great interest emerging as promising photovoltaic materials with a high 20.8% efficiency, but lead pollution is still a problem that may hinder the development and wide spread of MAPbI3 perovskites. To reduce the use of lead, we investigated the structures, electronic and optical properties of mixed MAGexPb(1-x)I3 ...

Recently, due to problems arising from lattice mismatch in thin film growth in semiconductor manufacturing industry, researchers have shown great interest in modeling the physiochemical properties of cubic perovskite of types ABX3. They have put sizeable efforts to reduce error in the prediction of lattice constant (LC) of cubic perovskites. However, linear prediction models were developed usin...

The site incorporation mechanism of M dopants into ABO3 perovskites controls the overall defect chemistry and thus their transport properties. For charge balance reasons, incorporation onto the A site would require the creation of negatively charged point defects, such as cation vacancies, whereas incorporation onto the B site is accompanied by the generation of positively charged defects, typi...

We report on a new metal halide perovskite photovoltaic cell that exhibits both very high solar-to-electric power-conversion efficiency and intense electroluminescence. We produce the perovskite films in a single step from a solution containing a mixture of FAI, PbI2, MABr, and PbBr2 (where FA stands for formamidinium cations and MA stands for methylammonium cations). Using mesoporous TiO2 and ...

In the end of 1940s young soviet scientist Georgii Smolenskii discovered ferroelectric properties in lead titanate (PbTiO 3) [1] and found an anomaly in the temperature dependence of the dielectric constant in lead zirconate (PbZrO 3) [1,2]. This encouraging result was also independently obtained by G. Shirane [3] and G. Roberts [4]. Based on this data, Smolenskii came to the conclusion that Pb...