Solution Processed Optical Coatings For Solar Cell Applications

In the recent past the demand for higher energy conversion efficiency of solar cells is on the rise. Extensive research is carrying out and many new methods have been proposed by changing either fabrication process or implementation of anti-reflection coatings. In this thesis, the solution processed omni directional anti-reflection coatings have been demonstrated on commercial amorphous silicon solar cells and on fabricated organic solar cells. A simple convective coating technique is utilized to deposit spherical silica micro-particles on the commercial amorphous silicon solar cells and on fabricated organic solar cells. In order to investigate the behavior of solar cells at different times of the day, we have measured the output electrical parameters of the solar cell at different angles of light incidence from 0o to 60o with a home built set up. It was found that spherical surface texture reduces the reflectivity in the wavelength regime of 400-1200 nm and efficiency enhancement was also observed at all angles of light incidence and as high as 12% was achieved at larger incident angles. This method proved to be very cost effective because of the use of simple deposition techniques and easy way of processing. Another technique, dip coating process, has also been studied to obtain inorganic dielectric particle based Distributed Bragg Reflectors (DBR) for applications in one-dimensional photonic crystal, and in resonance cavity photonic devices. The properties of the fabricated DBR structures were characterized with reflection measurement and other structure characterizations. All these convective coating and dip coating processes enable simple fabrication of optical structures for novel photonic device applications.