Tuning photovoltaic performance of co-doped graphene quantum dots

Abstract

The photovoltaic performance of graphene quantum dots (GQDs) faces instability due to structural irregularities. To understand optoelectronic properties, this study employs density functional theory (DFT) to investigate nitrogen-doped GQDs (NGQDs) co-doped with sulfur (N,S) and phosphorous (N,P). Co-doping with N and S or N and P reduces electron-hole pair separation, increasing thermal loss in GQDs with graphitic N functionality. N,S co-doping heightens surface defect likelihood, while N,P co-doping diminishes it. The chemical reactivity of NGQDs is influenced by polar solvent choice, unlike excited-state properties of GQDs doped with other elements. NGQDs with graphitic and pyrrolic N functionalities outperform co-doped GQDs in photovoltaic performance due to enhanced parameters. This study guides rational design of electronic devices using GQD materials.