Preparation Of CIGS Solar Cells On Novel PI Substrates

Energy crisis and global warming make governments around the world promoterenewable energy development, and solar energy in the renewable energy industry holds animportant position. CIGS thin film solar cells have received a rapid development, and becomethe international PV industry hotspot. Flexible CIGS thin film solar cells have become aresearching focus because of their high mass ratio of power, portable, flexible and suitable forbuilding integration.Usually, substrate temperature in the preparation of CIGS thin film is higher than500℃.We need to consider the thermal expansion coefficient of different materials. The thermalexpansion coefficient of polyimide and CIGS material is too different to impact the adhesionbetween the film and substrate. How to solve this problem will be one of key technologies todeposit high performance flexible CIGS thin film solar cells.This paper proposes an idea which using a kind of rigid substrates to prepare flexiblesolar cells. We make the polyimide film and soda-lime glass combine together to form a kindof composite substrate to deposit CIGS films. After all the preparing processes completed, thesolar cell will be isolated from soda-lime glass, and become a kind of solar cell withpolyimide substrate.The novel PI substrates are prepared by spin coating and curing processes, and CIGS thinfilms are deposited by a single-stage process and a three-stage process at low temperature inthe co-evaporation equipment. The paper make a detailed description and experimentalanalysis about how to improve the adhesion of CIGS thin film, the morphology, formationmechanism and gradients of CIGS thin film deposited by the single-stage process and thethree-stage process. Through optimization and analysis of the preparing processes, we finallyobtained the efficiency of flexible CIGS thin film solar cells reach6.92%..