Antimony sulfide selenide prototype photovoltaic modules surpassing 4% conversion efficiency under the sun - A technological outlook

We discuss the performance under the sun, at intensity 1000 W/m(2), of prototype photovoltaic modules of antimony sulfide selenide thin films, Sb2S1.06Se1.94, with optical bandgap, 1.35 eV. At 26 degrees C, a module of seven series-connected cells of total active area 6.97 cm(2) has conversion efficiency (eta) of 4.38% with open-circuit voltage (V-oc), 3.13 V; short circuit current (I-sc), 21.2 mA and maximum power (P-m) of 30.5 mW. Under steady state operation at 58 degrees C, eta is 3.54%; V-oc, 2.58 V; I-sc, 21.73 mA and P-m 24.6 mW. Four such prototype modules connected in series of total area 26.8 cm(2) give at 26 degrees C, eta of 4.4%; V-oc, 12.54 V, I-sc, 21.66 mA and P-m 118 mW. At 58 degrees C, these values drop to eta, 3.24%; V-oc, 10.46 V; I-sc, 20.02 mA and P-m 87 mW. We prepared these modules on commercial SnO2:F (FTO) with cell structure FTO/CdS(90 nm)/Sb(2)S(1.06)se(1.94)(210 nm)/C-Ag, where the electrodes of area approximately one cm(2) each are of colloidal graphite and silver paints. We deposited CdS film from chemical bath and Sb2S1.06Se1.94 film, by thermal evaporation of Sb2S3, Sb2Se3, and SbCl3. This report contains basic properties and technological outlook for this absorber.