Black Phosphorus/TiO2 Composite Photoanode with Enhanced Photoelectrical Performance

Black phosphorus (BP) shows broad application in optical, photoelectric and semiconductor fields. Herein, BP nanosheets and few-layer phosphorene were prepared by means of a solvent exfoliation method. The absorption and fluorescence spectra of BP were measured and dye-sensitized solar cells (DSSCs) were fabricated using BP/TiO2 films as working electrodes. The results show that the light-absorption ability of BP depends on the number of layers and few-layer phosphorene can absorb ultraviolet light (260-325 nm) specifically. The decrease of interfacial transport resistance and the increase of the utilization of sunlight favor the enhanced photoelectric conversion (eta) of approximate to 38% compared with TiO2 films. The stability of few-layer phosphorene was also studied and the reduction of the corresponding eta was mainly due to the defects caused by chemical etching which impeded electron transport. In all, there is a good reason to believe that if we can find an effective way to solve the seal problems in the devices, few-layer phosphorene will be an excellent candidate in optical, photoelectric and semiconductor fields.