The Effect of Transparent Conductive Oxide Substrate on the Efficiency of SnGe-perovskite Solar Cells

Abstract

The efficiency of Sn-perovskite solar cells has been dramatically improved by adopting the inverted structure solar cells and is expected to reach the efficiency of lead-based perovskite solar cell. We have observed fluctuations in the efficiency of the same perovskite material due to the type of TCO substrates. In this study, we investigated the influence of TCO substrates on the solar cell characteristics of SnGe-perovskite solar cells. It was found that the efficiency of the SnGe-perovskite solar cell is better with fluorine-doped tin oxide (FTO) substrate (9.24%) than indium-doped tin oxide (ITO) substrate (7.72%). The improvement of the efficiency of the cell with FTO substrate is contributed by the improvement in the short-circuit current J_sc and V_oc. The high transmittance of FTO substrate enhanced the J_sc while the V_oc is influenced by the Fermi level of the transparent conductive oxide film. Although there is a difference in the surface roughness between TCO substrates, there is no direct influence on the device performance that can be observed.