Solar cells and prototype modules of variable bandgap antimony sulfide selenide thin films made by chemical deposition

Antimony sulfide (Sb2S3) with a bandgap (Eg) of 1.88 eV and antimony selenide (Sb2Se3) with an Eg, 1.1 eV, both of orthorhombic crystalline structure, can form thin films of Sb2SxSe3-x of variable bandgap, 1.1 - 1.88 eV. In chemical deposition, thin films of Sb2S2.3Se0.7 (film, C) with Eg, 1.58 eV and Sb2S0.46Se2.54 (film, H) with Eg, 1.31 eV were obtained by varying the selenosulfate - to - thioacetamide (SS:TA) ratio from 0.033 (C) to 0.3 (H) in the deposition bath. Solar cell structures of fluorine-doped tin oxide (FTO)/CdS (75 - 80 nm)/Sb2SxSe3-x (90 - 180 nm)/graphite were made with colloidal graphite paint applied on an area 0.25 cm2 and heated in nitrogen (20 torr pressure) for 30 min. Silver paint was applied on the FTO around the demarked cells and on the graphite electrode. Under standard test conditions, the Sb2S2.3Se0.7 solar cell (C) gave: Vocof 0.552 V, Jscof 8.6 mA/cm2, fill factor (FF) 0.32 and efficiency (7) of 1.52 %. Solar cell of Sb2S0.46Se2.54 (H) gave: 0.427 V, Jscof 23.1 mA cm - 2, and FF of 0.54, with 7 of 5.32 %. Solar cell prepared with variable bandgap C-H films improved 7 to 6 % with Vocof 0.461 V, and Jscof 24.73 mA cm - 2. Prototype modules of six series connected cells of variable bandgap absorbers of Sb2SxSe3-x, each of 0.9 cm2 in area (active area, 5.4 cm2), gave under standard operating condition, Vocof 2.8 V, with short circuit current (Isc) 17.24 mA, FF of 0.46 with 7 of 4 %. Variable bandgap Sb2SxSe3-x prototype modules produced by chemical deposition is a viable option for their continued improvement.