Development of Textured Electrode, Index Matching Layer and Nanostructured Materials for Light Trapping inside Photovoltaic devices

Abstract

In order to reduce the energy harvesting cost, numerous efforts have been made to replace crystalline silicon solar cells with thin film based solar cells. The device efficiency of thin film photo-voltaic devices needs to be improved. Currently, surface texturing based light trapping technologies have been used to improve the device efficiency of photo-voltaic devices. In this paper, we demonstrate experimentally that surface textured hydrogenated ZnO:Al films as transparent conducting oxide (TCO) electrode and nanostructured materials in solar cells improve the anti-reflection properties of TCO coated glass substrate. These surfaces scatter the incident light inside the active layer of solar cells. Scattering of light on textured and nanostructured surface causes increase in average light path length inside active layer which results in increased absorption coefficient. Amorphous silicon solar cells fabricated on textured TCO layer show increase in device efficiency. Silicon nitride film was used as index matching layer between glass and TCO and increase in transmittance was observed. Silicon nanowires were grown using PECVD for their application in solar cells. Metal (Indium) nanoparticles were used for plasmonic light trapping inside solar cells. It was observed that textured TCO, index matching layer and plasmonic nanoparticles techniques improve the device efficiency while nanowires based devices need more optimization to get higher efficiency. © 2018 Elsevier Ltd.