Nature of the band gap of halide perovskites ABX ₃ ( A = CH ₃ NH ₃ , Cs; B = Sn, Pb; X = Cl, Br, I): First-principles calculations

Abstract

The electronic structures of cubic structure of ABX3(A=CH3NH3, Cs; B=Sn, Pb; X=Cl, Br, I) are analyzed by density functional theory using the Perdew–Burke–Ernzerhof exchange–correlation functional and using the Heyd–Scuseria–Ernzerhof hybrid functional. The valence band maximum (VBM) is found to be made up by an antibonding hybridization of B s and X p states, whereas bands made up by the π antibonding of B p and X p states dominates the conduction band minimum (CBM). The changes of VBM, CBM, and band gap with ion B and X are then systematically summarized. The natural band offsets of ABX3 are partly given. We also found for all the ABX3 perovskite materials in this study, the bandgap increases with an increasing lattice parameter. This phenomenon has good consistency with the experimental results.

Unveiling the Low‐Temperature Pseudodegradation of Photovoltaic Performance in Planar Perovskite Solar Cell by Optoelectronic Observation

“…As shown in Figure S4 of the Supporting Information, the transmittivities of CH 3 NH 3 PbI 3 almost remain unchanged from 325 to 200 K, except for the red shift of the absorption onset. The red shift is responsible for reducing the bandgap with decreasing temperature, which is consistent with that calculated elsewhere . Since the optical absorption efficiency is assumed to be almost the same here and the exciton binding energy is reported to be 32 ± 5 meV, the degradation of PV performance at low temperature is caused by the inefficient separation and collection of photogenerated carriers due to the low electric field in PSC .…”

Understanding surface chemistry during MAPbI3 spray deposition and its effect on photovoltaic performance

“…45,46 XPS analysis previously revealed that the total oxygen atomic concentration calculated from the integrated area under the core level O 1s increased for decreasing MAPbI 3 film thickness (Fig. 2a).…”

Bandgap tunable Csx(CH3NH3)1−xPbI3perovskite nanowires by aqueous solution synthesis for optoelectronic devices

“…Hybrid perovskites have attracted great interest due to their tunable bandgaps and superior energy conversion properties. The bangap tuning were generally implemented by changing the composition by halogen anion [10][11][12][13][14] or cation [15][16][17] Nowadays, the synthesis methods of perovskite NWs were ascribed to solvent evaporation assisted self-assembly method [19][20][21][22][23][24] . And most reports utilized organic polar solvent such as N, N-dimethyformamide (DMF), dimethyl sulfoxide(DMSO) in solution method.…”