Photoconductive thin films of AgSbS2 with cubic crystalline structure in solar cells

Polycrystalline thin films of AgSbS2 of thickness 140 nm and crystalline structure matching that of the mineral cuboargyrite (a = 0.5652 nm) are obtained by heating chemically deposited thin films at 150–320 °C. These films are deposited at 40 °C from a solution mixture containing antimony‐thiosulfate complex and Ag‐nitrate at a mole‐fraction Ag/(Ag+Sb) of 0.31. The as‐deposited films are progressively transformed to cubic‐AgSbS2, with the fraction of crystalline matter at 3.7% after heating at 150 °C and 98% at 280 °C. The crystalline grain diameter is limited to 8–11 nm. The amorphous film has an optical band gap (Eg) of 2.03 eV and the film heated at 320 °C has an Eg of 1.79 eV. The crystalline films are photoconductive; with electrical conductivity of 10−5 Ω−1 cm−1 under an intensity of illumination, 1000 W m−2 (tungsten‐halogen). The mobility–lifetime product of the material is 7.5 × 10−7 cm2 V−1. A solar cell, SnO2:F/CdS/AgSbS2(420 nm)/C, has open circuit voltage, 0.615 V; short‐circuit current density, 1.67 mA cm−2; and conversion efficiency, 0.57% for air‐mass 1.5 global solar radiation. Estimate for the maximum photo‐generated current density for cubic‐AgSbS2 is 16 mA cm−2; hence a supplementary absorber is recommended for future development of the solar cell.