Investigation on copper based chalcogenide nanomaterials and thin films for photovoltaic applications

Abstract

The zenith of energy conversion and storage devices started at the mid of 19th century. Consequent to the scarcity of fossil fuels and its effects on environment, most of the countries seeking for an eco-friendly energy sources. Apart from silicon, plethora of materials analysed and demonstrated such as, compound semiconductors (CuxS, CdTe, and CuInS2 etc.), organic semiconductors and perovskite materials (ABX3). Among, transition metal chalcogenides such as CdTe, CdS, Cu2-xS, CuInS2 etc., promised that it could serve a potential photovoltaic material. Hence, demonstrating cost effective compound semiconductors such as CuCdS2, CuZnS2 and Cu2NiSnS4 might deliver better efficiency. It is interesting to study the optoelectronic properties of these materials since, the binary forms of these materials (Cu2-xS, CdS, ZnS, SnS, etc.) have distinctive electrical and optical properties with one another. Hence, this thesis work majorly focuses on material aspects such as, optimization of synthesis and deposition of CuCdS2, CuZnS2 and Cu2NiSnS4 and optoelectronic properties. The thesis contains seven chapters in which, chapter one gives an introduction about history and dawn of photovoltaics. Moreover, limitations on efficiency and methods to surpass the limits are explained. Furthermore, it explains significance of compound semiconductors over silicon are elucidated. In addition, it interpreted emergence of binary, ternary and quaternary chalcogenides, its limitations and performance over the past decades are reported. Chapter two deals with characterization techniques used to analyse the synthesized and deposited materials. In which, origin of the analysis and working principles, are explained. Further, instrumentation of the characterizations with its advantages and limitations are given in detailed.Chapter three described about the effects of solvents on the synthesis of CuCdS2 nanoparticles. This chapter subdivided in to two parts, the first part is about oleylamine mediated CuCdS2 nanoparticles synthesized by colloidal