Large thermoelectric power factors in black phosphorus and phosphorene

TL;DR

This study uses first-principles calculations to evaluate the thermoelectric properties of black phosphorus and phosphorene, revealing their high power factors and potential for thermoelectric applications at room temperature.

Contribution

It provides the first detailed theoretical analysis of thermoelectric performance in black phosphorus and phosphorene, highlighting their large power factors and promising ZT values.

Findings

Black phosphorus and phosphorene have large thermoelectric power factors at room temperature.

Bulk black phosphorus can achieve a ZT of 0.22 with n-type doping.

Phosphorene can reach a ZT of 0.30 using bulk lattice thermal conductivity estimates.

Abstract

The electronic properties of the layered black phosphorus (black-P) and its monolayer counterpart phosphorene are investigated by using the first-principles calculations based on the density functional theory (DFT). The room-temperature electronic transport coefficients are evaluated within the semi-classical Boltzmann theory. The electrical conductivity exhibits anisotropic behavior while the Seebeck coefficient is almost isotropic. At the optimal doping level and room temperature, bulk black-P and phosphorene are found to have large thermoelectric power factors of 118.4 and 138.9 {\mu}Wcm-1K-2, respectively. The maximum dimensionless figure of merit (ZT value) of 0.22 can be achieved in bulk black-P by appropriate n-type doping, primarily limited by the reducible lattice thermal conductivity. For the phosphorene, the ZT value can reach 0.30 conservatively estimated by using the bulk lattice thermal conductivity. Our results suggest that both bulk black-P and phosphorene are potentially promising thermoelectric materials.