Electrochemical Atomic Layer Deposition of Ag2S Quantum Dots Sensitized TiO2 Nanorods Array Photoanodes and Cu2S Counter Electrode for Solar Cells

Abstract

High coverage Ag2S quantum dots were tightly deposited on the surface of TiO2 nanorod arrays by electrochemical atomic layer deposition (ECALD) method. To match the polysulfide electrolyte, a thin layer of Cu2S was deposited on FTO substrate directly by ECALD as well. The structure, composition and morphology of the deposits were characterized by X-ray diffraction, transmission electron microscopy, energy dispersion spectroscopy, and scanning electron microscopy, respectively. The results suggest that the ECALD method can significantly enhance the coverage of Ag2S quantum dots on TiO2 surface and control the size or deposited thickness of Ag2S quantum dot. A broad absorption range of the visible light was observed in the UV–vis absorption spectra of the Ag2S deposited electrodes. The photovoltaic performance of the cell based on the ECALD deposited Ag2S/TiO2/FTO photonanode and Cu2S/FTO counter electrode achieves a maximum short-circuit current density of 4.25 mA/cm2, with a power conversion efficiency of 0.41% at AM 1.5 solar light of 100 mW/cm2.