Composition Engineering for the Content and Distribution of Sb–O, Se, S in Antimony Sulfoselenide Thin Films Using Chemical Bath Deposition for Efficient Solar Cells

Abstract

Herein, Na2SSeO3 solutions are prepared by hydrothermal method at 140 °C for 8 h using Se powder and Na2SO3 solution (the molar ratios of Se:Na2SO3 = 1:4, 1:5, 1:6) and the chemical composition of Na2SSeO3 solutions is analyzed by X‐ray photoelectron spectroscopy. Sb2S y Se3−y thin films are prepared by chemical bath deposition (CBD) at 90 °C for 5 h and subsequently annealed at 375 °C for 10 min and etched by N‐butyldithiocarbamic acid solution in DMF. The effect of the Na2SSeO3 solution, growth solution volume, etching on the thickness and chemical composition of Sb2S y Se3−y thin films, and the power conversion efficiency (PCE) of the corresponding solar cells is systematically investigated. The result reveals that the Na2SSeO3 solutions may be the mixing solutions containing Na2SSeO3, Na2S2SeO6, Na2S2Se2O6, Na2Se. When the molar ratio of Se:Na2SO3 and growth solution volume is 1:5 and 56 mL and the Sb2S y Se3−y thin films with annealing are etched, the PCE of Sb2S y Se3−y solar cells is 8.00% with spiro‐OMeTAD and 8.43% with spiro‐OMeTAD:TMT‐TTF. The PCE of 8.43% is the highest value for Sb2S y Se3−y solar cells using CBD and demonstrates that the composition engineering is an important strategy for improving the PCE of Sb2S y Se3−y solar cells using CBD.