Electrochemical atomic layer deposition of Bi2S3/Sb2S3 quantum dots co-sensitized TiO2 nanorods solar cells

Abstract In this study, high coverage and uniformly distributed Bi 2 S 3 and Sb 2 S 3 quantum dots (QDs) are deposited simultaneously on the surface of TiO 2 nanorods (NRs) via electrochemical atomic layer deposition (ECALD) method. The structure, morphology and composition of the deposits are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersion spectroscopy analysis (EDS), respectively. The results show that the deposits are of Bi 2 S 3 and Sb 2 S 3 compound semiconductor, and the Bi 2 S 3 /Sb 2 S 3 QDs cover on the top and side surface of TiO 2 NRs homogeneously. EDS analysis demonstrates that the ratio of both S to Sb and S to Bi are approximately 3:2, indicating that ECALD method can well control the deposition of each element. Owing to the better light absorption property and reduced recombination possibility of Bi 2 S 3 /Sb 2 S 3 QDs co-sensitized solar cells, the power conversion efficiency reaches 0.67% with a short-circuit current density of 4.83 mA cm −2 at AM 1.5 solar light of 100 mW cm −2 , which is much higher than that of Bi 2 S 3 or Sb 2 S 3 QDs sensitized solar cells.