Photodeposition of Ag2S on TiO2 nanorod arrays for quantum dot-sensitized solar cells

Ag 2 S quantum dots were deposited on the surface of TiO 2 nanorod arrays by a two-step photodeposition. The prepared TiO 2 nanorod arrays as well as the Ag 2 S deposited electrodes were characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscope, suggesting a large coverage of Ag 2 S quantum dots on the ordered TiO 2 nanorod arrays. UV–vis absorption spectra of Ag 2 S deposited electrodes show a broad absorption range of the visible light. The quantum dot-sensitized solar cells (QDSSCs) based on these electrodes were fabricated, and the photoelectrochemical properties were examined. A high photocurrent density of 10.25 mA/cm 2 with a conversion efficiency of 0.98% at AM 1.5 solar light of 100 mW/cm 2 was obtained with an optimal photodeposition time. The performance of the QDSSC at different incident light intensities was also investigated. The results display a better performance at a lower incident light level with a conversion efficiency of 1.25% at 47 mW/cm 2 .