An Overview of the First Principles DFT Exploration of Various Properties of the Individual Layers of Perovskite Solar Cells

The rapid improvement in efficiency of perovskite solar cells has made them the key to future developments in photovoltaics and their properties are of great interest to the academic community. Perovskites exhibit a host of intriguing properties, such as ferroelectricity, superconductivity, magnetoresistance, birefringence and piezoelectricity, due to their unique crystal structure. In comparison, perovskite solar cell performance has improved from 3.1 percent in 2009 to 24.4 percent in 2019. As a vast number of elements can be assembled to form perovskite structures, the physical, optical and electrical properties of perovskite can be engineered and optimized selectively. It is possible to access the previously unknown structural properties, opto-electronic properties and operating parameters of these materials with high precision through theoretical and analytical modeling. This paper seeks to describe a few abilities of DFT hybrid functionals to investigate the electronic, structural and optical properties of compounds that constitute different layers of a perovskite solar cell using software packages such as VASP, WIEN2k etc. The effect of doping on the electronic properties of different layers of perovskite solar cells, including band gap, visible light absorption, relaxation time of holes and electrons using DFT, is also examined in this paper which in turn defines the optimum separation of charge. The consequence of adding an intermediate band gap in the perovskite structure using G0W0+SOC approach-based DFT methods is also discussed here. A study on the impact of different intrinsic defects present in perovskite structures using VASP or WIEN2k package with DFT calculations is also discussed. The importance of modeling the interfaces of different layers of perovskite solar cells with DFT packages is explored with the aid of selected material examples and representative interfaces.