Investigation of Mo films deposited on high temperature polyimide substrate by magnetron sputtering for flexible CIGS thin film solar cells application

Abstract

CuIn(1-x)GaxSe2 (CIGS) is one of the most promising thin film photovoltaic technologies for commercial application. Flexible Polyimide (PI) substrate based CIGS solar cells have lots of advantages such as lightness, flexibility, shatter resistance, and so on. However, due to the low glass transition temperature of the commercial PI substrate, the performances of flexible CIGS solar cell and module are much lower than that of CIGS solar cell and module on rigid glass substrate. In this study, we report a two-step process for preparation of PI with high decomposition temperature (Td) and 5% weight loss temperature (Td,5) of 551 and 596 °C, respectively. In addition, Mo films were deposited on the high temperature PI substrate by magnetron sputtering. The effect of deposition pressure on the growth rate, resistivity, microstructure, and surface morphologies of the magnetron sputtering deposited Mo film were investigated. We have shown the Mo coated high temperature PI films has the potential for substrate application in high efficiency flexible CIGS solar cell fabrication.