Functional prototype modules of antimony sulfide selenide thin film solar cells

Abstract Thin film solar cells of antimony sulfide selenide in the cell structures of: (i) FTO/CdS (120 nm)/Sb 2 S 0.6 Se 2.4 (500 nm)/C-Ag and (ii) FTO/CdS (120 nm)/Sb 2 S 1.4 Se 1.6 (500 nm)/C-Ag are found to reach solar-to-electric energy conversion efficiency ( η ) exceeding 5%. Here FTO was F-doped SnO 2 thin films of sheet resistance 7 Ω; CdS thin films were prepared by chemical bath deposition at 80 °C from solutions of cadmium nitrate and thiourea; thin films of Sb 2 S x Se 3-x were prepared from powder mixtures of Sb 2 S 3 and Sb 2 Se 3 in vacuum thermal evaporation; and C Ag were colloidal graphite electrodes on which colloidal silver paint was applied and dried. The absorber layers in solar cells have optical bandgap 1.40 eV (Sb 2 S 0.6 Se 2.4 ) – 1.43 eV (Sb 2 S 1.4 Se 1.6 ) and photoconductivity, 10 −5  Ω −1  cm −1 . Averaged Solar cell parameters for (i) are: open circuit voltage ( V oc ), 0.476 V; short circuit current density, 21.7 mA/cm 2 ; Fill Factor ( FF ), 0.50; and η , 5.16%; and for (ii) the corresponding values are: 0.500 V; 22.4 mA/cm 2 ; 0.47; and 5.26% reporting on cell area 0.5 cm 2 . The best among solar cell (i) has η of 5.7% and (ii) is of 5.5%. Prototype modules consisting of seven series-connected solar cells, each of 1 cm 2 in area of (ii) are: V oc , 3.2 V; short circuit current, 21.1 mA; FF , 0.39; η , 4.1% for active area (7 cm 2 ) and power, 28.8 mW. This module is able to light-up under the sun, blue light emitting diode of 20 mW nominal power at 2.75–3.0 V. Overall prospects for further work on these solar cells are discussed.