High Ambipolar Mobility and Long-Range Carrier Transport in Violet Phosphorus Nanosheet

Carrier transport capacity with high mobility and long-range diffusion length holds particular significance for the advancement of modern optoelectronic devices. Herein, we have unveiled the carrier dynamics and transport properties of a pristine violet phosphorus (VP) nanosheet by a transient absorption microscopy. Under the excitation (2.41 eV) above the exciton band, two photoinduced absorption peaks with the energy difference of approximately 520 meV emerge within a broadband transient absorption background which originates from the prompt generation of free carriers and the concomitant formation of excitons (lifetime of 467.21 ps). This observation is consistent with the established band-edge model of VP. Intriguingly, we have determined the ambipolar diffusion coefficient and mobility of VP to be approximately 47.32 cm²·s^-1 and 1798 cm²·V^-1·s^-1, respectively, which further indicate a long-range carrier transport of approximately 2.10 μm. This work unveils the significant carrier transport capacity of VP, highlighting its potential for future optoelectronic and excitonic applications.