AuNRs attached TiO NPs modified by cobalt-imidazolate frameworks as exceptional materials to improve the energy conversion efficiency of dye-sensitized solar cells

This work reports a significant improvement in both the open-circuit voltage ( V OC ) and current density ( J ) of dye-sensitized solar cells (DSSCs) using gold nanorod-modified TiO 2 nanoparticles (TiO 2 /AuNRs) together with a cobalt-imidazolate framework (ZIF-67) as an efficient photoanode. It was demonstrated that adding ZIF-67 (8 wt%) to TiO 2 NPs increased the V OC by 160 mV and J by 2.5 times. This observation was described based on the significant increase in the amount of adsorbed dye in the presence of highly porous ZIF-67, which boosts the photoanode's light harvesting. Modifying TiO 2 NPs with AuNRs also caused a remarkable enhancement in J (∼ 2.8 times), which can be explained via electron transfer between the TiO 2 conduction band and AuNRs. It can result in a more efficient inhibiting effect on the interfacial charge recombination processes in TiO 2 /AuNRs/ZIF-67 because of the formation of a Schottky barrier at the interface between TiO 2 and Au. These effects were confirmed by the reduction in the photoluminescence intensity of TiO 2 in the presence of AuNRs. More reduction in the photoluminescence intensity was observed when ZIF-67 was added. The prepared photoanode showed an outstanding improvement in the overall efficiency of the DSSC ( η ) to 8.38% compared to the bare TiO 2 -based photoanode (1.83%). The notable improvement in the TiO 2 /AuNRs/ZIF-67 performance confirmed its practicality for high-efficiency DSSCs. The incorporation of gold nanorod-modified TiO 2 nanoparticles (TiO 2 /AuNRs) along with cobalt-imidazolate frameworks (ZIF-67) into the photoanode of dye-sensitized solar cells resulted in a notable enhancement in energy conversion efficiency.