Phosphorene-AsP Heterostructure as a Potential Excitonic Solar Cell Material - A First Principles Study

TL;DR

This study uses first principles calculations to show that phosphorene-AsP heterostructures have suitable electronic and optical properties for efficient excitonic solar cells, with promising charge separation and transport characteristics.

Contribution

It demonstrates, through density functional theory, that phosphorene-AsP heterostructures are promising materials for excitonic solar cells with optimal band gaps and type-II alignment.

Findings

Band gaps are within the optimal range for XSCs.

Charge transport is faster along the Γ-X direction due to lower effective masses.

The heterostructure exhibits a type-II band alignment, favoring charge separation.

Abstract

Solar energy conversion to produce electricity using photovoltaics is an emerging area in alternative energy research. Herein, we report on the basis of density functional calculations, phosphorene/AsP heterostructure could be a promising material for excitonic solar cells (XSCs). Our HSE06 functional calculations show that the band gap of both phosphorene and AsP fall exactly into the optimum value range according to XSCs requirement. The calculated effective mass of electrons and holes show anisotropic in nature with effective masses along ${\Gamma}$-X direction is lower than the ${\Gamma}$-Y direction and hence the charge transport will be faster along ${\Gamma}$-X direction. The wide energy range of light absorption confirms the potential use of these materials for solar cell applications. Interestingly, phosphorene and AsP monolayer forms a type-II band alignment which will enhance the separation of photogenerated charge carriers and hence the recombination rate will be lower which can further improve its photo-conversion efficiency if one use it in XSCs.