Phase transformation and photoelectrochemical characterization of Cu/Bi and Cu/Sb based selenide alloys as promising photoactive electrodes

Abstract

Two photoactive chalcogenide compounds, copper bismuth selenide (CBSe) and copper antimony selenide (CASe), have successfully been prepared via a robust and facile solvothermal route. The phase transformation characteristics from the triclinic to orthorhombic crystal structure were clearly evinced by replacing Bi3+ with Sb3+ ions. The changes in the microstructure and electronic composition of each compound have been monitored using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy characterization techniques. The fabricated CBSe film showed large values of absorption coefficient >105 cm-1, good electrical conductivity, and charge carrier mobilities. The values of optical bandgap energy were estimated to be 0.99 and 1.18 eV for CBSe and CASe alloys, respectively. The electrochemical impedance spectroscopy measurements possessed lower resistance for CBSe electrodes. The photovoltaic performance results for the fabricated CBSe photoelectrochemical cells exhibited the maximum short-circuit current (Isc) of 6.22 mA, open-circuit voltage (Voc) of 0.492 V, fill factor of 63.9%, and power conversion efficiency of 1.94%. Finally, the as-prepared CBSe and CASe ternary alloys have possessed a good capability for dye sensitized solar cell and superconductor's applications.