Lead-free organic inorganic hybrid halide perovskites: An emerging candidate for bifunctional applications

Lead halide perovskite-based solar cells have developed significantly over the past few years and have proven to be suitable for photovoltaic applications thanks to several intriguing characteristics, including low cost, high absorption coefficient, long carrier diffusion length, low exciton binding energies, etc. However, the toxicity and stability of lead seemed to be the main challenges; therefore, a replacement was required. As an alternative, lead-free mixed organic-inorganic halide perovskite has revolutionized science and technology. The power conversion efficiency of these lead-free perovskite-based solar cells has dramatically increased to ∼20%, given the well-known uses of solar cells. As a result, due to their efficiency and low-cost processing, these are more promising and comparable with silicon-based PV applications. Excluding lead, due to its highly toxic and low stability nature, other replacements such as Sn, Ge, Bi, In, Sb, etc., are already considered suitable clients for different applications. Formamidinium, methylammonium, and other larger-sized organic cations demonstrated their compatibility with flexible other dimensional structures such as 2D, 1D, and 0D for enhancing stability. The diverse synthesis procedure make the preparation of these lead-free mixed organic metal inorganic halide much easier. Apart from various optoelectronic applications, the variation of the A and B cation sites led to different other catalytic, sensing, and energy applications making these materials suitable for bi/multi-functional applications. This review article has focused on the various properties and related preparation processes of these hybrid mixed halide perovskites. Different applications of these hybrid materials were also reviewed and summarized, including bi/multi-functional applications. This paper provides an overall performance of mixed hybrid halide perovskites from synthesis through multifunctional applications.