Efficient TiO(2) Surface Treatment Using Cs(2)CO(3) for Solution-Processed Planar-Type Sb(2)S(3) Solar Cells

We report a highly effective surface treatment method for planar-type Sb(2)S(3) solar cells by employing a Cs(2)CO(3)-modified compact TiO(2) (c-TiO(2)) electron transport layer. It is found that surface treatment using a Cs(2)CO(3) solution can shift the work function of c-TiO(2) 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-TiO(2)(/Cs(2)CO(3))/Sb(2)S(3)/P3HT/Au structure significantly improved from 2.83 to 3.97%. This study demonstrates that the introduction of Cs(2)CO(3) on a c-TiO(2) layer is a simple and efficient way to adjust the work function of the electron transport layer and fabricate high-performance planar-type Sb(2)S(3) solar cells.