Double-Sided Heat-Exchange CBD System for Homogeneous Zn(O,S) Thin Films in Highly Efficient CIGS Solar Devices

Zn(O,S) thin film as one of the most promising alternative buffer layers in Cu(In,Ga)Se-2 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 cm(2)) and over 10% for flexible modules (36 cm(2)) 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.