Structural, morphological, electrocatalytic activity and photocurrent properties of electrochemically deposited FeS_2 thin films

摘要

Iron pyrite (FeS~(2)) thin films have been deposited onto indium doped tin oxide coated glass substrate using two sulphur anion sources such as thiourea [(NH~(2))~(2)CS] and sodium thiosulfate [Na~(2)S~(2)O~(3)] by electrochemical deposition method. The profilometer analysis shows that roughness of FeS~(2)thin films obtained low for (NH~(2))~(2)CS than the Na~(2)S~(2)O~(3)as an anion sources. The X-ray diffraction analysis confirms that as-deposited FeS~(2)thin films shows cubic system with (200) plane preferential orientation for using (NH~(2))~(2)CS. When Na~(2)S~(2)O~(3)is used it results in a cubic system (200) along with hexagonal (201) of FeS reflection peak signifying a mixed phase. The optical studies of the thin films deposited using (NH~(2))~(2)CS shows the bandgap at 0.98 eV, while the bandgap for Na~(2)S~(2)O~(3)was 0.92 V. Atomic force microscopy images shows a crack free and densely packed morphology of FeS~(2)thin films obtained for both anion sources. The electrochemical impedance spectra study of FeS~(2)thin film exposed that less of charge transfer resistance and fine conductivity was obtained from the (NH~(2))~(2)CS than Na~(2)S~(2)O~(3)as a sulfur source. The photocurrent study of as-deposited thin films shows that a significant by enhanced photocurrent response for (NH~(2))~(2)CS compared to Na~(2)S~(2)O~(3)used thin films. The electrocatalytic activity of as deposited FeS~(2)thin films shows that better I_(−)/I~(3)_(−)redox couple when investigated by the cyclic voltammetry. The as-deposited FeS~(2)thin films obtained from the (NH~(2))~(2)CS as an anion source is capable of to substituting the for platinum electrode.