Two-stage-processed AgSbS2 films for thin-film solar cells

AgSbS2 has shown promise as an earth-abundant, sustainable light-harvesting material for thin-film solar cells owing to its suitable optoelectronic properties and high stability. Here, we report the fabrication of AgSbS2 thin films using a two-stage process (sequential evaporation of Sb/Ag layers and sulfurization at 300-400 degrees C for 30 min) and their characterization. X-ray diffractometry revealed the formation of Ag3SbS3 and Sb2S3 phases, single-phase AgSbS2, and slight decomposition of AgSbS2 and the emergence of monoclinic AgSbS2 at sulfurization temperatures of 300, 350, and 400 degrees C, respectively. The AgSbS2 films have a cubic crystal structure with a lattice parameter (a) of 0.565 nm. X-ray photoelectron spectroscopy confirmed that the valence states of Ag, Sb, and S were +1, +3, and -2, respectively. Microstructural analysis of the film prepared at 350 degrees C revealed highly crystalline, large-grains with an average grain size of 5 mu m. Optical absorption studied suggested that the AgSbS2 film prepared at 350 degrees C exhibited a direct bandgap of 1.61 eV. Hall measurements revealed an electrical resistivity of 1.52 x 10(4) Omega cm, hole mobility of 84.5 cm(2)V(-1)s(-1), and a carrier concentration of 7.95 x 10(12) cm(-3) for the AgSbS2 film prepared at 350 degrees C. Finally, AgSbS2 solar cells with glass/Mo/AgSbS2/CdS/indium-tin-oxide/Ag configuration were fabricated (optimal device parameters: efficiency, 1.1%; open-circuit voltage, 519.6 mV; short-circuit current density, 6.63 mA/cm(2); and fill factor, 31.0%). The device processing conditions must be optimized to further improve the efficiency.

Automated summary

This study reports the fabrication and characterization of AgSbS2 thin films, which showed different phase structures at different sulfurization temperatures. The optical and electrical properties of the films were analyzed. AgSbS2 solar cells were also fabricated, exhibiting a certain level of efficiency. However, the device processing conditions need further optimization.