Optoelectronic Characterization of Photovoltaic Devices & Application of Nanofibers for Charge Storage

Abstract

The Dye Sensitized Solar Cells (DSSCs) have shown very less improvement in photo-conversion efficiency in the last decade. The basic understanding of these devices is still not very sound. The oxygen vacancies in TiO2 substrate have a significant role in the performance of DSSC. The optoelectronic transient technique is one of the crucial measurements employed to study the fundamental properties of DSSC’s. In this work we have used optoelectronic current and voltage transient measurements and electrochemical impedance spectroscopy as tools to study the performance of DSSC’s with respect to the presence of oxygen vacancies. The brief introduction to the thesis is presented in chapter 1. A brief overview of the characterization techniques of the photovoltaic devices is presented in chapter 2 along with a general outline of the instruments and methods used for the characterization of the nanomaterials. Chapter 3 comprises of the detailed analysis on the effect of oxygen vacancies on the performance of dye sensitized solar cells. Recently, nanofibers have got a very high significance due to their interesting opto-electronic properties over other nanostructures. Hence we synthesized nanofibers with a self-designed electro-spinning instrument and used these for different energy applications. In section B, chapter 4 is dedicated to the general introduction of 1D nanostructures of metal oxides and carbon based nanostructures and their characterization tools. The application of Au-TiO2 nanostuctures as a scattering layer in quantum dot solar cells is discussed in chapter 5. NiFe2O4 – CNF (carbon nanofibers) as a cathode material for hybrid supercapacitor is discussed in chapter 6.