P-type In3+-doped Cu12Sb4S13 thin films deposited by spray pyrolysis method: Investigation of structural, optical, electrical, and electrocatalytic properties

Abstract

We demonstrated p-type In3+-doped Cu12Sb4S13 (CAS) thin films using a spray pyrolysis method. The alteration in the shape of N2 adsorption isotherm curves is associated with changes in the structural and adsorption properties of the as-synthesized thin films. The accurate diameter (D) value was calculated based on the Burstein-Moss effect and the calculated values were close to the exciton Bohr radius (a0) of the polycrystalline CAS material. This can be confirmed by noting that the determination of Eg − Eph, Eg + Eph and EgBulk values was consistent with the a0 value of the polycrystalline CAS material. The decrease in hole resistivity (ρh) of 414.36 × 10−2 to 3.71 × 10−2 Ω cm could improve the carrier mobility (μ) of 0.12 × 10−2 to 10.93 × 10−2 cm2/V·s with the increase of the relaxation time (τ) from 0.068 × 10−17 s to 6.22 × 10−17 s for 0.0–1.5 wt% In3+ doping, respectively. For the study of electrocatalytic properties, the highest exchange current density (J0) value of 0.949 mA/cm2 was obtained at 0.5 wt% In3+ doping. This attributed to the superior electrocatalytic activity and charge transfer property of the thin films and electrolyte interfaces.