MULTIDIMENSIONAL ENGINEERING OF PEROVSKITES FOR OPTOELECTRONIC APPLICATIONS

Abstract

The importance of perovskite-based solar cells – the emerging materials for photovoltaic applications – heavily relies on the increasing energy demands in recent years. The evolutionary progress has been observed in the area of photovoltaic technologies due to the intrinsic optoelectronic and light harvesting properties that perovskite possesses. In order to address the ambient instability challenges posed to perovskite solar cells, structural modifications of perovskite material are suggested by combining perovskites of different dimensionalities for the solar cell’s application. The research on the topic of multidimensionality of dual-halide Cs-based perovskites (i.e., CsPbI2Br) is not conventional and little is reported on the different types of 2D perovskite formation inducing materials suitable for this perovskite system. Most of the reported 2D/3D structures are based on organic and hybrid perovskites, while the inorganic PVKs are limited to CsPbI3. Thus, in this research the main focus is directed towards investigation of intrinsic properties of dual-halide CsPbI2Br with incorporation of inorganic Cs+ spacer cation via CsCl posttreatment, which in combination resembles the properties of 3D perovskites incorporated with the 2D structures. The obtained results show that the CsCl post-treatment changes the morphology of perovskite, its composition and crystal lattice, adjusts optical properties as well as improves the performance of the PSC. The obtained champion PSC devices after the post-treatment showed a 48% improvement of the PCE (from 10.9% to 16.2% for the champion PSCs), and maintained stable performance under 20% RH condition.