Wide range tuning of band gap energy of A3B2X9 perovskite-like halides

Enhanced visible light absorption in layered Cs3Bi2Br9 through mixed-valence Sn(ii)/Sn(iv) doping

“…The wide range of ions that can be incorporated on both the cation and anion sites of an choice of composition. 2 Several strategies have been employed, from alloying on the halide site, 8,[23][24][25] which usually produces a band gap response similar to that seen in the perovskites, to doping on the B-metal site, which may lead to introduction of filled states within the band gap, 26,27 or band bowing. [26][27][28] Recently, Ghosh et al studied a mixed valence perovskite (CH 3 NH 3 )AuBr 3 , containing Au(I) and Au(III), which resulted in significant visible light absorption.…”

Electronic, optical, and thermoelectric properties of perovskite variants A 2 BX 6 : Insight and design via first‐principles calculations

“…their toxicity and low chemical stability. The most common compositional and structural alternatives are Sn and Te based perovskites (CH 3 NH 3 SnI 3 , CH 3 NH 3 GeI 3 ), 21,22 Ruddlesden‐Popper hybrid perovskites, 23,24 halide double perovskites A 2 BB′X 6, 25,26 and A 3 B 2 X 9 perovskites 25,27,28 . A new variant of the perovskite family of the type A 2 BX 6 has been recently obtained by doubling the unit cell length of 3D perovskite ABX 3 in each crystallographic direction.…”

“…The most common compositional and structural alternatives are Sn and Te based perovskites (CH 3 NH 3 SnI 3 , CH 3 NH 3 GeI 3 ), 21,22 Ruddlesden-Popper hybrid perovskites, 23,24 halide double perovskites A 2 BB 0 X 6, 25,26 and A 3 B 2 X 9 perovskites. 25,27,28 A new variant of the perovskite family of the type A 2 BX 6 has been recently obtained by doubling the unit cell length of 3D perovskite ABX 3 in each crystallographic direction. The structure is formed by removing half of the octahedral B-site atoms of ABX 3 , yielding ordered vacancies with isolated BX 6 octahedral cluster, as shown in Figure 1.…”

A Review on Lead-Free Hybrid Halide Perovskites as Light Absorbers for Photovoltaic Applications Based on Their Structural, Optical, and Morphological Properties

“…These compositions are inclined to develop zero-dimensional, one-dimensional, and two-dimensional (2D) perovskite-like halide absorbers with properties featuring varying sizes agreeing to the direction of measurement due to the purpose of quantitative relations between the reactants [27]. These perovskite-like halide absorbers are a structurally rich group of mixed organic−inorganic halide perovskites from the extensive family of A 3 B 2 X 9 structures, where A represents monovalent positively charge ions = Cs + , Rb + , or CH 3 NH 3 + alias MA + ; B stands for the positively charged trivalent metal ions = Bi 3+ , Sb 3+ ; and X denotes negatively charged ions of halides = (Cl − , Br − , or I − ) employed as active photovoltaic absorbers [45,[131][132][133].…”