Surfactant mediated synthesis of bismuth selenide thin films for photoelectrochemical solar cell applications

In the present report, nanostructured bismuth selenide (Bi₂Se₃) thin films have been successfully deposited by using arrested precipitation technique (APT) at room temperature. The effect of three different surfactants on the optostructural, morphological, compositional and photoelectrochemical properties of Bi₂Se₃ thin films were investigated. Optical absorption data indicates direct and allowed transition with a band gap energy varied from 1.4 eV to 1.8 eV. The X-ray diffraction pattern (XRD) revealed that Bi₂Se₃ thin films are crystalline in nature and confirmed rhombohedral crystal structure. SEM micrographs shows morphological transition from interconnected mesh to nanospheres like and finally granular morphology. Surface topography of Bi₂Se₃ thin films was determined by AFM. Compositional analysis of all samples was carried out by energy dispersive X-ray spectroscopy (EDS). Finally, all Bi₂Se₃ thin films shows good PEC performance with highest photoconversion efficiency 1.47%. In order to study the stability of Bi₂Se₃ thin films four cycles are repeated after gap of one week each. Further PEC performance of all Bi₂Se₃ thin films are also supported by electrochemical impedance (EIS) measurement study.