Influence of Al-doped ZnO transparent electrodes on thin-film interference in Cu2ZnSn(S,Se)(4) thin-film solar cells prepared via a sputtering method

Abstract

Transparent electrodes are often regarded as a trade-off between transmittance and sheet resistance, although the effect of thin-film interference on the performance of an optoelectronic device is significant. In this paper, we report the effect of optical thin-film interference of an Al-doped ZnO (AZO) transparent electrode on the performance of Cu2ZnSn(S,Se)(4) (CZTSSe) solar cells. First, we distinguished the transmittance in the overall wavelength region (450-800 nm) of the AZO transparent electrode from the transmittance in the maximum absorption region for CZTSSe solar cells (550-700 nm). From the results, a thicker AZO transparent electrode showed higher transmittance (87.1%) than that of a thinner AZO transparent electrode (82.9%) in the maximum absorption region. These electrodes were applied in CZTSSe solar cells, which showed a difference of up to 26% in power conversion efficiency. In addition, the colors generated by the optical interference between the AZO transparent electrodes. We anticipate that our results will be useful for improving the performance and/or color tuning of thin-film solar cells for application in building-integrated photovoltaics.