Microwave‐assisted hydrothermal synthesis of Cu‐doped TiO 2 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 (V oc ). Considerable efforts have been made to increase the V oc of DSSCs by suppressing charge carrier recombination dynamics, co‐sensitization, and other strategies. Herein, we report an enhancement of the V oc by the incorporation of Cu into TiO 2 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 Cu 2+ into TiO 2 lattice raises its conduction band (CB) edge and shifted the Fermi level upwards, which contribute towards enhanced V oc . A significant enhancement in V oc from 0.714 to 0.781 V was observed by the Cu incorporation. An optimized 1 wt% Cu modified TiO 2 DSSC has shown an efficiency of 6.94% with a high V oc of 0.762 V.