Physicochemical and Electrocatalytic Performance of Chromium doped Iron Pyrite Thin Films

Chromium (Cr³⁺) doped iron pyrite (FeS2) thin films were deposited on ITO substrate by a facile electrochemical deposition process. The effect of chromium content on structural, optical, electrical, morphological, and electrocatalytic behavior of the pyrite thin films were examined. X - ray diffraction studies confirmed the formation of cubic crystal structure of deposited thin films. Atomic force microscopy results indicate that Cr³⁺ doping has strong influence on crystallinity, surface roughness and grain size of as-deposited thin films. Further, bandgap reduction was found in Cr³⁺ doped FeS2 thin films. The interfacial charge resistance of fabricated thin films was investigated by electrochemical impedance spectroscopy and 3 mole % Cr³⁺ doped FeS2 thin films showed excellent conductivity with a low charge transfer resistance of 49 Ω. Further, the electrocatalytic performance of the prepared pyrite thin films was investigated. Cr doped thin films were found to exhibit better performance. Anti-structural modeling was opted to investigate the characteristics of defects in fabricated thin films and it was established that Cr³⁺substitutionmay form cation (Fe²⁺) vacancies which could be responsible for enhanced photochemical and electrochemical activities in Cr-doped FeS2 thin films.