研究目的

Investigating the structural, electronic, optical and elastic properties of CsSnI3?xBrx perovskites for solar cell applications using first-principles study.

研究成果

FP-LAPW technique is used to measure the physical properties of CsSnI3?xBrx. It is observed that unit cell volume and lattice constant decrease as halide ion changed from I to Br. The value of ‘B’ increases and there is no significant effect is observed on its pressure derivative except for CsSnI2Br. In both GGA and mBJ-GGA potential based structural graphs symmetry point do not change and lies at R symmetry point. It is found that the band gap increases as the halide ion Br change from (x = 0, 1, 2, 3). The offbeat structures appear in the spectra of e2 is mainly due to transitions from Cs and halide ions p-states from the VB to vacant states in the CB. Optical properties consisting on dielectric function, refractive index, extinction coefficient and absorption coefficients are calculated and discussed. The maximum absorption coefficient was found with the composition CsSnBr3 than CsSnI3. The high absorption power and direct band gaps in ultraviolet range predicts that these materials are suitable for solar cell applications. Elastic properties of these materials show that these materials are ductile because they have low ‘B’ values. Their ratio of bulk ‘B’ to ‘G’, anisotropic coefficient A and Poisson ratio of the materials CsSnI3, CsSnI2Br, CsSnIBr2, and CsSnBr3 revealed that they are ductile, anisotropic and ionic in nature. The findings of this study are predictive and can be used toward experimental work.

研究不足

The mixed halide contents are pioneered in this study and therefore, no data is in hand for estimation.