Plasmonic Effect with Tailored Au@TiO₂ Nanorods in Photoanode for Quantum Dot Sensitized Solar Cells

Quantum dot sensitized solar cells (QDSCs) are recognized as one of the most promising candidates in converting solar energy into electric energy. The ideal solar cells should meet the demands including high light-harvesting capacity and charge transfer rate. However, the current power conversion efficiency of QDSCs remains low, due to insufficient light absorption of the photoanode and the sluggish charge extraction rate from quantum dots to TiO2. In the device, TiO2 performs the function of loading quantum dots and transmitting photogenerated electrons; thus, the TiO2 films should be carefully designed and constructed. In this work, the as-prepared Au nanorods coated with TiO2 are incorporated into TiO2 film electrode. Benefiting from the plasmonic effect of Au nanorods, the resulted photoanodes exhibit an enhanced light-scattering effect, consequently improving the light-harvesting efficiency of the photoanode. Meanwhile, photoelectric characterization reveals that the formed interface of Au nanorods/TiO2 can not only inhibit the charge recombination process but also accelerate charge transfer within TiO2. The resultant plasmonic devices based on Zn–Cu–In–Se quantum dots and Cu2S/brass CEs exhibit a power conversion efficiency of 8.58%, much higher than that of the pristine TiO2 photoanode based one (7.27%). This work puts up a versatile strategy for fabricating high efficiency QDSCs.