Organic-inorganic hybrid and inorganic halide perovskites: structural and chemical engineering, interfaces and optoelectronic properties

This review aims to capture the emergent scenario of research in the field of organic-inorganic hybrid perovskites and inorganic halide perovskites as fuelled by the continuing excitement about these materials, their unique properties and their immense application potential in photovoltaics and optoelectronics. While some spectacular successes have already been achieved in respect of these applications, several challenges have also been encountered in terms of the stability of these materials under different ambients and stimuli, and their integration with other functional materials to generate new device architectures. Towards this end, this review discusses pertinent strategies to tune and control their device-worthy properties and eliminate their shortcomings to the extent feasible. These include (a) intelligent doping in these structurally and chemically sensitive systems, (b) the role of defects and strategies to mitigate them via innovative synthetic controls, (c) molecular engineering to control the dimensionality and new phases in these materials, and (d) the emergent understanding about the structure-chemistry-property relationships, especially the photophysical properties. We also address the bearing that these issues have on the ultimate realisation of robust high-efficiency solar cells, either in stand-alone or tandem configurations, as well as on high-performance light-emitting diodes. The insights gained by first-principles density functional theory calculations to understand the experimental observations and to predict new material designs are also discussed. The review is concluded with a section on the summary and outlook, wherein the authors' perspective on the emergent scenario is presented.