Effect of indium(III) doping on chemosynthesized MoBi2Te5 thin films and it’s photoresponse property

Abstract

In the present investigation, using self-organized, cost effective arrested precipitation technique MoBi2Te5 and indium(III) doped MoBi2Te5 thin films have been successfully synthesized onto the ultrasonically cleaned glass and fluorine-doped tin oxide coated glass substrates. Structural, morphological, optical, electrical properties and photoelectrochemical property of MoBi2Te5 and indium(III) doped MoBi2Te5 thin films have been investigated by using UV–Vis spectrophotometer, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), electrical conductivity (EC), thermoelectric power (TEP) measurement techniques. XRD study revealed that thin films were nanocrystalline in nature with rhombohedral crystal structure. SEM micrographs demonstrated that uniform allocation of grains with uneven spherically shaped, distributed over entire surface. Also, enhanced grains size is clearly observed after effective indium(III) doping. EDS showed that the composition of MoBi2Te5 and In:MoBi2Te5 thin films was in good stoichiometry. Optical absorption study shows direct allowed type of transition with optical band gap energy decreases from 1.44 to 1.37 eV with indium(III) doping. Synthesized and doped thin films shows semiconducting behavior confirmed from EC measurements. TEP measurements study reveals that the films were of n-type nature. Finally, MoBi2Te5 and indium(III) doped MoBi2Te5 thin films were employed for the fabrication of photoelectrochemical solar cells. Indium(III) doped thin films exhibited significant improvement of power conversion efficiency (η) of 0.205 % as compared to as-synthesized MoBi2Te5 thin films. Such improvement in power conversion efficiency might be due to crystalline nature, good incorporation of indium(III) in ternary thin films and improved surface morphology.