Study of solvent effect on structural and photoconductive behavior of ternary chalcogenides InBiS3-In2S3-Bi2S3 composite thin films deposited via AACVD

Abstract

In the present work ternary composite InBiS3-In2S3-Bi2S3 (IBS) thin films are developed using a homogeneous mixture of precursors [Bi(S2CN(C2H5)2)3]2 (1) and [In(S2CNCy2)3]2py (2), separately in toluene and chloroform solutions at 500°C under an inert atmosphere of argon gas via aerosol assisted chemical vapor deposition (AACVD) technique. The phase purity, chemical composition and morphological study of both the films deposited from toluene and chloroform solutions are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and Field emission scanning electron microscopy (FESEM). The surface morphology showed rod like structure of the films developed from toluene while the films grown from chloroform solution give flake like shapes. The UV-visible spectroscopy explicated that the thin films developed from toluene and chloroform solutions show wide range absorption in whole visible region. Linear Scan voltammetry results show that both the films give negligible dark current, however, the films fabricated from toluene solution give a sharp steep curve with maximum photocurrent density of 2.3 mAcm-2 at 0.75 V vs Ag/AgCl/3M KCl using 0.05 M sodium sulphide solution under AM 1.5 G illumination (100 mWcm-2), while the film grown from chloroform generates a photocurrent density of 2.1 mAcm-2 under similar conditions. The LSV outcomes are further supported by electrochemical impedance spectroscopy (EIS) that gives charge transfer resistance (Rct) value of 8,571 ω for the films developed from toluene as compared to films fabricated from chloroform with Rct value of 12,476 ω.