An overview of the decompositions in organo-metal halide perovskites and shielding with 2-dimensional perovskites

Despite their facile synthesis and unprecedently increased power conversion efficiency, there is a dark side of organo-metal halide perovskites solar-cell i.e. their intrinsic environmental instability. A little moisture, harsh ultraviolet-light, and slightly higher thermal stress demolish it quickly into its constituents. A solution to these instability issues is a prerequisite to commercialize this next-generation solar-cell technology. To understand the degradation mechanism in perovskites, different models have been proposed. Similarly, to prevent them from environmental hazards, various strategies have been adopted. For instance, 2D-perovskites are introduced as a stable alternative to their 3D-counterparts. However, due to their wider bandgaps, 2D-perovskites failed to compete with 3D-perovskites in the race of power conversion efficiency. Therefore, a hybrid 2D/3D-perovskites are introduced which brought together, the high power conversion efficiency of 3D-perovskites and extended environmental stability of their 2D counterparts. The first section of this review discusses in detail about the proposed mechanisms behind the perovskites decompositions due to environmental factors including; humidity, radiation, and thermal stress. While, the second part summarizes several strategies adopted to prevent perovskites degradation; particularly, the strategy of shielding 3D-perovskites with its 2D counterpart, which is the most promising one. Furthermore, this review provides details of the overall progress been made in the field of pure-2D, quasi-2D, and hybrid-2D/3D perovskites solar-cells. In the end, a brief outlook on the challenges remaining in the way of commercialization of perovskites solar-cells and our opinion to their possible solutions is given.