Insulating oxide buffer layer formed by sol-gel method for planarization of stainless steel substrate of a-Si:H thin film solar cell

摘要

The planarization of flexible stainless steel (SS) foils was investigated for the application of flexible solar cells. The sol-gel SiO_2 film containing nanoparticles was evaluated for a buffer layer on SS foils, and methods to improve the adhesion of SiO_2 film to SS foil were studied. The improvement of adhesion by adding Al_2O_3 matrix was discussed by analyzing the interface between Al_2O_3-SiO_2 film and SS foil. The usefulness of sol-gel buffer layer was also verified by comparing the performance of single junction a-Si:H thin film solar cells fabricated on bare SS foil and buffer layer-coated SS foil. The cell characteristics such as V_(oc).J_(sc). Fill factor, and efficiency were all improved by adopting the buffer layer. The efficiency of the cell on buffer layer-coated and non-textured SS foil was 6.1% whereas the efficiency was 4.9% on bare SS foil.