Efficient TiO2 Surface Treatment Using Cs2CO3 for Solution-Processed Planar-Type Sb2S3 Solar Cells

Abstract

We report a highly effective surface treatment method for planar-type Sb₂S₃ solar cells by employing a Cs₂CO₃-modified compact TiO₂ (c-TiO₂) electron transport layer. It is found that surface treatment using a Cs₂CO₃ solution can shift the work function of c-TiO₂ upward and reduce its surface roughness. As a result, compared with the power conversion efficiency of untreated solar cells, that of the treated solar cells with a glass/FTO/c-TiO₂(/Cs₂CO₃)/Sb₂S₃/P3HT/Au structure significantly improved from 2.83 to 3.97%. This study demonstrates that the introduction of Cs₂CO₃ on a c-TiO₂ layer is a simple and efficient way to adjust the work function of the electron transport layer and fabricate high-performance planar-type Sb₂S₃ solar cells.

Keywords: Cs2CO3; Electron transport layer; Planar-type Sb2S3 solar cell; Solution process; Surface treatment.