High efficiency CIGS solar cells on flexible stainless steel substrate with SiO2 diffusion barrier layer

The copper indium gallium selenium (CIGS) thin film is recognized as the most potential material for photovoltaics applications, and the thin film solar cell with flexible substrate makes the application scenarios more extensive and the product advantages more obvious. In this contribution, we prepared high efficiency CIGS thin film solar cells on flexible stainless steel substrate by three-stage coevaporation method. In this study, silicon dioxide film was proposed as the diffusion barrier layer of iron, chromium and other impurity elements in stainless steel flexible substrate to the CIGS absorber, which were found to reduce the performance of the device. The thickness of the SiO2 barrier layers varying from 0 to 1000 nm was studied. The structure, crystal morphology and electrical properties of each sample were studied. The results showed that the conversion efficiency increased with the increase of thickness of sputtered silicon dioxide barrier until the thickness is greater than 200 nm.