Antimony Selenide Absorber Thin Films in All-Chemically Deposited Solar Cells

Chemically deposited antimony selenide (Sb 2 Se 3 ) thin film has a coexisting antimony oxide (Sb 2 O 3 ) phase which may be converted to crystalline Sb 2 Se 3 thin films with an optical bandgap of 1.13 eV when heated at 300°C in nitrogen in the presence of selenium vapor. Instead of this, if the heating is done with an Sb 2 S 3 thin film on the chemically deposited Sb 2 Se 3 :Sb 2 O 3 thin film, a solid solution with the coexisting oxide phase (Sb 2 Se 3-x S x :Sb 2 O 3 ) is produced. The optical bandgap of such absorber material is 1.34-1.58 eV. The as-deposited thin films as well as those produced by heating are photoconductive. They were incorporated into solar-cell structures developed entirely by chemical deposition on SnO 2 :F-coated commercial transparent conductive oxide (TCO) glass. The cell structure, TCO/CdS/Sb2Se3:Sb203/PbS, showed an open-circuit voltage (V oc ) of 540 mV and short-circuit current density (J sc ) of 0.67 mA/cm 2 . In the cell TCO/CdS/Sb2Se 3-x S x :Sb 2 O 3 /PbS produced by heating in nitrogen, V oc is 520 mV, J sc is 4.2 mA/cm 2 , and conversion efficiency (η) is 0.66%. The scalability of the all-chemically deposited solar cell is demonstrated in four series-connected cells of area 1 cm 2 each, showing short-circuit current of 1.5 mA and V oc of 1.9 V under sunlight.