Synthesis of Phosphorene Quantum Dots from Red Phosphorus

Phosphorene quantum dots (PQDs) are most commonly derived from high-cost black phosphorus, while previous syntheses from the low-cost red phosphorus (Pred) allotrope are highly oxidised. Herein, we present an intrinsically scalable method to producing high quality PQDs, by first ball-milling Pred to create nanocrystalline Pblack and subsequent reductive etching using lithium electride solvated in liquid ammonia. The resultant PQDs are spontaneously soluble as monolayers in tertiary amide solvents, laterally confined to < 100 nm dimension, photoluminescent, and crystalline with low oxygen content. This new method presents a scalable route to producing quantities of high quality PQDs for academic and industrial applications.