MODULATING THE PEROVSKITE SINGLE CRYSTAL CHARACTERISTICS WITH POLYMER ADDITIVES

Abstract

Perovskite materials are a new class of materials that have gained popularity in the field of research due to its various advantageous optical and electronic properties making them a suitable candidate to make optoelectronic devices. Polycrystalline thin films have been widely used for photovoltaic applications, but it suffers from various drawbacks such as grain boundaries leading to defects, instability issues, prone to degradation due to moisture absorption, etc. Apart from these issues the surface roughness also hinders the performance of the thin film devices. Perovskite single crystals on the other hand show excellent properties such as lesser defects due to the absence of grain boundaries, high charge carrier mobility, longer carrier diffusion length, efficient light absorption coefficient, tunable band gap and low cost solution processability. These properties make single crystal perovskite materials a suitable candidate for photodetector applications. Many researchers are trying to find ways to lessen the defects that still prevail in the perovskite single crystals. One way to passivate the defect is to use appropriate polymers in the precursor solution. In doing so many instances have been proven to passivate the surface defects. The main challenge is to choose the polymer in question. In this research work, two polymers polyacrylic acid (PAA) and polyvinyl alcohol (PVA) are used as passivating agents. Apart from the defect passivation, the study of its optoelectronic properties was also done and used for photodetector applications.