Strong Optical Excitation and High Thermoelectric Performance in 2D Holey-Phosphorene Monolayer

Abstract

Through density functional theory (DFT)-based computations, a systematic exploration of the newly predicted 2D phosphorene allotrope, namely holey-phosphorene (HP), is carried out. It is revealed that HP shows a semiconducting nature with an indirect bandgap of 0.83 eV upon Perdew-Burke-Ernzerhof (PBE) functional. Then, to survey the optical features, a (G₀W₀)-based approach is employed to solve the Bethe–Salpeter equation to derive the intra-layer excitonic effects. It is derived via the absorption spectrum, that HP presents an excitonic binding strength of 1.47/1.96 eV along the x/y-direction with the first peak of the absorption at 0.92/0.43 eV for the x/y-direction. The thermoelectric properties are also explored in detail and reveal a very high thermal power value along with an enhanced figure of merit (ZT) of about 3.6. The 2D HP monolayer for thermoelectric performance has high thermoelectric conversion efficiency (TCE) and is estimated to be about 22%. All these outstanding findings may be attributed to the quantum confinement effect of the porous geometry of the 2D HP nanosheet, thereby confirming its relevance as a prospect for high-performance optoelectronic and thermoelectric engineering systems.