Pyrite as prospective absorber material for monograin layer solar cell

Abstract

FeS2 monograin powders as absorber materials in monograin layer solar cells were grown in the molten phase of two different flux materials - in liquid sulphur (S) and in potassium iodide (KI) at different temperatures - at 500 °C, 550 °C, 600 °C in S and at 740 °C in KI. The cooling temperature profiles were modified to preserve the pyrite phase of material until room temperature was reached. FeS2 microcrystals, synthesized in sulphur and recrystallized in molten KI as flux, had cubic structure of pyrite phase with stoichiometric composition, confirmed by X-ray diffraction, Raman, and energy dispersive X-ray analyses, respectively. The grown FeS2 crystals exhibited n-type conductivity determined by hot probe measurements. The powder crystals were fixed in monograin membranes for making heterostructures with p-type nickel oxide (NiO) buffer layer. Charge carrier concentrations 6.2 × 1016 and 2.5 × 1017 cm−3, were found from capacitance-voltage measurements using FeS2/NiO heterostructures and FeS2/Pt Schottky diodes, respectively.