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

Abstract

In this study, high coverage and uniformly distributed Bi2S3 and Sb2S3 quantum dots (QDs) are deposited simultaneously on the surface of TiO2 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 Bi2S3 and Sb2S3 compound semiconductor, and the Bi2S3/Sb2S3 QDs cover on the top and side surface of TiO2 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 Bi2S3/Sb2S3 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 Bi2S3 or Sb2S3 QDs sensitized solar cells.