Antimony Chalcogenide/Lead Selenide Thin Film Solar Cell with 2.5% Conversion Efficiency Prepared by Chemical Deposition

Antimony sulfide-selenide solid solutions offer optical band gaps, E-g, in the 1-1.88 eV interval; and lead selenide offers E-g upward of its bulk value, 0.28 eV, depending on the extent of quantum confinement. In this work, thin film solar cells of SnO2:F/CdS/Sb-2(Se/S)(3)/PbSe/C-Ag are developed by chemical deposition of the thin films on transparent conductive oxide (TCO) glass. To prepare the solar cell, first a CdS thin film of 100 nm in thickness is deposited on the TCO from a solution containing Cd(II)-citrate complex. On this, a thin film is deposited from a solution containing potassium-antimony tartrate, thioacetamide and selenosulfate, which upon heating at 280 degrees C in nitrogen ambient results in a Sb2S1.2Se1.8 film of 150 nm in thickness with an E-g of 1.67 eV. PbSe thin film 110 nm in thickness is deposited on it from a solution of Pb-citrate complex and selenosulfate, with crystalline grain diameter 10 nm, and E-g of 1.86 eV. The cell shows open circuit voltage (V-oc), 454 mV, short circuit current density (J(sc)) 12.5 mA/cm(2), fill factor (FF) 0.44 and conversion efficiency (eta) 2.5%. The observed cell parameters are backed by a tentative energy level diagram and an estimate for the light generated current density. (C) 2013 The Electrochemical Society. All rights reserved.