Double-sided heat-exchange CBD system for homogeneous Zn(O,S) thin films in highly efficient CIGS solar devices

Abstract

Zn(O,S) thin film as one of the most promising alternative buffer layers in Cu(In,Ga)Se2 solar devices has drawn considerable attention and been intensively studied in recent years. However, the reliability of the fabrication process still impeded its industrial application. In this work, a self-designed double-sided heat-exchange chemical bath deposition (CBD) system was introduced to deposit large-area homogeneous Zn(O,S) thin films. Compared with the traditional CBD setup, the self-designed system possesses several advantages including fast heat-up, homogeneous heating, wide adaptability, and cost-saving. Intriguingly, based on the self-designed system, high-quality Zn(O,S) thin films with less amounts of OH− and O2− impurities were easily and successfully deposited without changing the recipe. Furthermore, we have also demonstrated the homogeneity of the solar cells made from the same substrate with a large area and adopted this technique for the fabrication of modules both in the laboratory and in our partner company Shinetech Co., Ltd. As a preliminary result, over 16% conversion efficiency for rigid modules (53 cm2) and over 10% for flexible modules (36 cm2) based on the self-designed deposition system were obtained. As a consequence, a deeper understanding may be provided to deposit high-quality and large-scale Zn(O,S) thin films and hopefully also applicable to industrial.