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

In the present report, nanostructured bismuth selenide (Bi2 Se3 ) 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 Bi2 Se3 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 Bi2 Se3 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 Bi2 Se3 thin films was determined by AFM. Compositional analysis of all samples was carried out by energy dispersive X-ray spectroscopy (EDS). Finally, all Bi2 Se3 thin films shows good PEC performance with highest photoconversion efficiency 1.47%. In order to study the stability of Bi2 Se3 thin films four cycles are repeated after gap of one week each. Further PEC performance of all Bi2 Se3 thin films are also supported by electrochemical impedance (EIS) measurement study.