Enhanced performance of dye-sensitized solar cells anodes modified with black phosphorus nanosheets

Black phosphorus (BP) has attracted increasing attention owing to its unique electronic and optoelectronic properties. In this account, BP nanosheets (BP-NS) with high concentration were prepared through organic salt trisodium citrate assisted exfoliation of BP crystal; then, an efficient photoanode for dye-sensitized solar cells (DSSCs) was developed using BP-NS/TiO2 composite. Compared to bare TiO2-based DSSC with power conversion efficiency of only 6.98%, the DSSCs assembled with BP-NS based photoanode showed enhanced performance by ca. 40%. Optimal values of photocurrent density (22.32 mA/cm(2)) and power conversion efficiency (9.73%) were achieved with DSSC comprising the BP nanosheets. The interaction at the interface between BP and TiO2 in BP/TiO2 played a crucial role in improving the performance, which benefit the charge separation and transfer. The interfacial interactions between black phosphorus and TiO2, and the corresponding chemical configurations were thoroughly investigated with TEM and XPS spectroscopy. Overall, the proposed route looks effective for enhancing DSSCs efficiencies and would hold potential prospects for future development of DSSCs anodes.