Combined SiO_2 antireflective coatings with MOCVD-ZnO:B to improve light absorption in thin-film solar cells

摘要

Boron-doped zinc oxide (ZnO:B or BZO) thin films prepared by metal organic chemical vapor deposition (MOCVD) are widely used as the front contact in thin-film solar cells. However, because reflection at the air/glass interface reduces the absorption of incident light, the short circuit current densities, as well as the efficiencies of the cells are deteriorated. To solve this problem, we proposed the combination of silicon dioxide (SiO_2) antireflective (AR) coatings prepared by a sol-gel dip-coating method, with MOCVD-BZO films as the new substrate of the cell. The novel structure of the substrate obtained is: SiO_2 AR coatings/glass/BZO. An improvement in the optical properties of the new substrate was achieved by destructive interference of the AR coatings at the coatings/air interface. Appling this novel substrate in amorphous silicon solar cells resulted in significant improvement of both the external quantum efficiency and the performance of the cell.