Study of self-powered and broadband photosensing properties of CdS/PbS-decorated TiO2 nanorods/reduced graphene oxide junction

Self-powered broadband photodetector was fabricated using PbS/CdS-decorated TiO2 nanorods (NRs). TiO2 NRs were grown using hydrothermal method and CdS/PbS layers were deposited by chemical bath deposition process. Metal-free top electrode of the photodetector was prepared using chemically reduced graphene oxide (rGO). PbS/CdS-decorated TiO2 NRs based photodetector showed significant photocurrent over broad spectral range. The maximum responsivity (Rλ)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(R_{\lambda } ) $$\end{document} and detectivity (Dλ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$D_{\lambda }$$\end{document}) of the photodetector at zero bias was obtained, ~0.34 A W–1 and ~162742.42 Hz1/2 W–1, respectively, at 400 nm. TiO2/CdS/PbS/rGO device showed sharp rise and decline of photocurrent under ON/OFF of white light. This device also demonstrated excellent self-powered nature with open circuit voltage ~0.40 V, short circuit current ~0.077 mA and power conversion efficiency ~0.16%.