2P-378 : Enhanced Photovoltaic Properties in Planar Sb 2 S 3 Solar Cells by TiO 2 Surface Treatment Using Cs 2 CO 3

Antimony sulfide (Sb2S3) has attracted attention as an absorber material due to its suitable band gap (~1.65 eV), high absorption coefficient (＞ 105 cm-1), high dielectric constant, and good band alignment with various hole transport layers, in addition to its cost effectiveness, low toxicity, and excellent air stability. Here, we reported a highly effective surface treatment method using cesium carbonate (Cs2CO3) for planar Sb2S3 solar cells. A power conversion efficiency (PCE) of 3.97% was achieved under AM1.5G illumination using a planar device consisting of FTO/Cs2CO3/TiO2/Sb2S3/P3HT/Au, which is significantly higher than that of the control planar device with blank TiO2 (2.83%). It is found that surface treatment using a Cs2CO3 solution can shift the work function of TiO2 upward and reduce its surface roughness. ** This work was supported by the DGIST R&D Programs of the Ministry of Science, ICT & Future Planning of Korea (19-ET-01).