Edge-Modified Phosphorene Antidot Nanoflakes and Their van der Waals Heterojunctions for Solar Cell Applications

Using the density functional method, we demonstrate that edge-modified phosphorene antidot nanoflakes (PANFs) and their van der Waals heterojunctions are the new entity for novel light–electricity conversion. We have herein studied H, OH, and CN edge-passivated PANFs (PANF_H, PANF_OH, and PANF_CN) of different lengths and pore sizes. Our study reveals that irrespective of the length and pore size, PANF_OH and PANF_CN show localized highest occupied molecular orbital and lowest unoccupied molecular orbital charge densities in nanoscale. This localization causes spatial charge separation, i.e., well-defined electron–hole puddle and thus has promise to be used in solar cell. The edge decoration effect of PANFs offers a versatile route to design PANF_H/PANF_CN and PANF_H/PANF_OH type-II staggered heterojunctions, where hole and electron charge carriers are localized on distinct donor and acceptor PANFs, respectively, and thus shows spatial charge separation, which reduces the electron–hole recombination and, in turn, prolongs carrier lifetime. Our results predict that the edge-modified PANFs-based heterojunctions show photoconversion efficiency of up to 4.6%, making it competitive with other two-dimensional heterojunction-based solar cells.