Inhibition of charge recombination for enhanced dye-sensitized solar cells and self-powered UV sensors by surface modification

The surface modification to inhibit charge recombination was utilized in dye-sensitized solar cells (DSSCs) and self-powered ultraviolet (UV) sensors based on SnO 2 hierarchical microspheres by TiO 2 modification. For DSSCs with SnO 2 photoelectrodes modified by TiO 2 , the power conversion efficiency (PCE) was improved from 1.40% to 4.15% under standard AM 1.5G illumination (100   mW/cm 2 ). The electrochemical impedance spectroscopy and open-circuit voltage decay measurements indicated that the charge recombination was effectively inhibited, resulting in long electron lifetime. For UV sensors with SnO 2 photoelectrodes modified by TiO 2 layer, the self-powered property was more obvious, and the sensitivity and response time were enhanced from 91 to 6229 and 0.15   s to 0.055   s, respectively. The surface modification can engineer the interface energy to inhibit charge recombination, which is a desirable approach to improve the performance of photoelectric nanodevice.