Effects of interface charge-transfer doping on thermoelectric transport properties of black phosphorene-F4TCNQ nanoscale devices

Abstract

Using first-principle-based density functional theory (DFT) combined with non-equilibrium Green's function (NEGF) method, we carry out a systematic study on thermoelectric transport properties of both armchair and zigzag black phosphorus nanoribbons (APNR and ZPNR) with physical adsorption of molecule F4TCNQ on their surfaces. The results indicate that APNR/F4TCNQ system is presented as a p-type semiconductor, and valence band edge of APNR system shifts to Fermi level (FL) due to surface charge transfer from APNR to F4TCNQ. Compared with pure APNR, thermal power S of APNR with F4TCNQ adsorption is increased from 270.8 μV/K to 1063 μV/K owing to the increase of state density induced from the emergence of resonance energy level near FL. Moreover, interface coupling and quantum interference effects inhibit phonon thermal conductance of A/ZPNR + F4TCNQ system significantly, and optimal thermoelectric figure of merit ZT of ZPNR/F4TCNQ system achieves 0.72 when μ = −0.5 eV at room temperature. This work provides a possibility for extensive application of high-performance two-dimensional organic–inorganic nanodevices in thermoelectric field, and it also has theoretical reference for developing self-assembled electronic device in practical applications.