Photoelectrochemical properties of PbS quantum dot sensitized TiO2 nanorods photoelectrodes

Abstract

The semiconductor PbS quantum dots (QDs) were synthesized on TiO₂ nanorods (NRs) via a successive ionic layer adsorption and reaction (SILAR) method. The deposition of PbS QDs on the TiO₂ NRs could enhance the ability of light absorption and improve the power conversion efficiency of the solar cell. The morphological features, crystal structures, optical properties, photoelectrochemical performances, electron transfer at the TiO₂-QDs/electrolyte interface and electron lifetime of the obtained PbS QDs/TiO₂ NRs photoelectrodes were characterized and discussed in detail. The results demonstrated that the photoelectrochemical performance of PbS QDs/TiO₂ NRs depends on the value of the SILAR cycle number. The highest photoelectric conversion efficiency of 0.77% is achieved at the SILAR cycle number n = 4 under one sun illumination (AM 1.5, 100 mW cm⁻²). The enlarged absorption edges to the visible region and the effective separation of photogenerated electron–hole pairs at the PbS QDs-TiO₂ NRs interface are attributed to the promotion of the power conversion efficiency.