Microwave‐assisted hydrothermal synthesis of Cu‐doped TiO2 nanoparticles for efficient dye‐sensitized solar cell with improved open‐circuit voltage

Summary An important reason for the underlying power conversion efficiency (PCE) of the dye sensitized solar cells (DSSCs) is the low open‐circuit voltage (Voc). Considerable efforts have been made to increase the Voc of DSSCs by suppressing charge carrier recombination dynamics, co‐sensitization, and other strategies. Herein, we report an enhancement of the Voc by the incorporation of Cu into TiO2 microstructure via microwave‐assisted hydrothermal synthesis. The prepared nanoparticles and the photoanodes were tested for their efficacy with various structural, optical, and electrical characterization tools. It was found that the incorporation of Cu2+ into TiO2 lattice raises its conduction band (CB) edge and shifted the Fermi level upwards, which contribute towards enhanced Voc. A significant enhancement in Voc from 0.714 to 0.781 V was observed by the Cu incorporation. An optimized 1 wt% Cu modified TiO2 DSSC has shown an efficiency of 6.94% with a high Voc of 0.762 V.