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

Abstract

The surface modification to inhibit charge recombination was utilized in dye-sensitized solar cells (DSSCs) and self-powered ultraviolet (UV) sensors based on SnO2 hierarchical microspheres by TiO2 modification. For DSSCs with SnO2 photoelectrodes modified by TiO2, the power conversion efficiency (PCE) was improved from 1.40% to 4.15% under standard AM 1.5G illumination (100mW/cm2). 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 SnO2 photoelectrodes modified by TiO2 layer, the self-powered property was more obvious, and the sensitivity and response time were enhanced from 91 to 6229 and 0.15s to 0.055s, 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.