Single crystal of two-dimensional mixed-halide copper-based perovskites with reversible thermochromism

Abstract

Facile synthesis of single crystal of two-dimensional mixed-halide copper-based perovskites with tunable band gaps and their capability of exfoliation and reversible thermochromism.

Single Crystals of Mixed‐Cation Copper‐Based Perovskite with Trimodal Bandgap Behavior

“…[15][16][17][18] Attributed to the fact that the cesium cation Cs + (167 pm) has a smaller ionic radius than the methyl ammonium cation (MA) + (217 pm) cations, the perovskite crystal lattice contraction is expected. [19] While mixed halides play an important role in tuning the properties and stability of hybrid perovskites beyond pure halide perovskites, [20][21][22] understanding the effect of inorganic/organic mixed cations on the perovskite crystal lattice is critical not only for reducing potential degradation pathways but also for obtaining tunable perovskites properties. [23] The bandgaps of mixed-cation lead-based perovskite Cs x (MA) 1À x PbBr 3 which revealed a bimodal distribution, with bandgaps close to those of pure MAPbBr 3 for x � 0.13 and pure CsPbBr 3 for x > 0.13 according to Liu and his colleagues.…”

“…Regarding to literatures, mixed-halides of all MA Cuperovskites, that is, (CH 3 NH 3 ) 2 Cu(Cl/Br) 4 , are easily exfoliated into two-dimensional (2D) perovskites. [20,21] On the other hand, mixed-halides of all Cs Cu-perovskites, that is, Cs 2 Cu(Cl/Br) 4 with different crystal structures depending on the halogen content, cannot be exfoliated into separated flakes. [42][43][44][45] Herein, easily exfoliated 2D mixed-halides of all Cs perovskite are prepared through using excess concentration of cesium bromide (CsBr).…”

Reversible Thermochromism in All‐Inorganic Lead‐Free Cs3Sb2I9 Perovskite Single Crystals

“…[18] Hayashi et al reported TCM in Cu-based perovskite (CH 3 NH 3 ) 2 CuCl x Br 4 −x thin films obtained by the exfoliation of its single crystals (SC). [19] Gao et al demonstrated TCM in double perovskite Cs 2 AgBiBr 6 . [20] But, these materials showed high temperature TCM that prompted us to look for materials that are stable and can show the TCM property at lower temperature.…”

“…reported TCM in Cu‐based perovskite (CH 3 NH 3 ) 2 CuCl x Br 4 − x thin films obtained by the exfoliation of its single crystals (SC). [ 19 ] Gao et al. demonstrated TCM in double perovskite Cs 2 AgBiBr 6 .…”

Enhanced Structural Stability and Pressure‐Induced Photoconductivity in Two‐Dimensional Hybrid Perovskite (C6H5CH2NH3)2CuBr4

“…[15] Using, Cu, as a cheap, earth-abundant and non-toxic element, to develop Cu-based 2D perovskite materials was expected to be an ideal substitute due to the stable structures and the antioxidant ability. [16] Unfortunately, the solar cell fabricated with a layered (CH 3 NH 3 ) 2 CuCl 4À x Br x perovskite as the light absorption layer only exhibited a photoelectric conversion efficiency (PCE) of 0.017 %, [17] which was severely limited by its wide band gap and poor carrier transport performance. Photovoltaic devices using perovskite-like (CH 3 CH 2 CH 2 CH 2 NH 3 ) 2 CuBr 4 and (FÀ C 8 H 8 NH 3 ) 2 CuBr 4 were reported to exhibit good stability in air with 50 % humidity for one day, but the conversion efficiency is still quite low at 0.51-0.63 %.…”