Preparation of Sb2S3 nanorod arrays by hydrothermal method as light absorbing layer for Sb2S3-based solar cells

Antimony sulfide (Sb2S3) as a stable and nontoxic semiconductor reveals great potential for photovoltaic devices. Sb2S3 has a one-dimensional crystal structure consisting of covalently bonded (Sb4S6)n ribbons stacking together through van der Waals force. This special structure results in anisotropic electrical and optical properties. Currently, most Sb2S3 photovoltaic device studies have been focused on the grain orientation in the Sb2S3 thin film absorbers. However due to the one-dimensional crystal structure, nanorods arrays is more favored for carrier directional transport between layers than bulk thin film. In this context, effective approaches to enhance the carrier mobility by applying Sb2S3 nanorod arrays as light absorber are urgently required. Herein this study introduces a hydrothermal method prepared Sb2S3 nanorod arrays that grown on certain substrates. Series of Sb2S3 nanorod arrays with different length, diameter, nanorod density per area, and hole mobility were fabricated by using different precursors or ligand and controlling reaction time. An efficiency of 1.46% and a hole mobility of 30.9 cm2 V–1 s–1 were attained with an optimized device structure of glass-fluorine-doped tin oxide/ZnO/ZnO–ZnS/Sb2S3 nanorod arrays/poly(3-hexylthiophene-2,5-diyl)/MoOx/Ag, which were 5.1 times higher in efficiency and 2.5 times higher in hole mobility than those of the control group using non-oriented randomly stacked nanorods as light absorber. This research provides an approach to fabricate Sb2S3 nanorod arrays and verifies the enhancement of hole mobility in Sb2S3 nanorod arrays, which provides a perspective for efficient Sb2S3-based solar cells.