Etching of Colloidal InP Nanocrystals with Fluorides: Photochemical Nature of the Process Resulting in High Photoluminescence Efficiency

The photoluminescence efficiency of InP nanocrystals prepared via the dehalosilylation reaction between indium chloride and tris-(trimethylsilyl)phosphine in mixtures of trioctylphosphine and trioctylphosphine oxide can be drastically improved by etching with fluorine compounds, as proposed several years ago by Micic et al. A systematic study reported in this communication revealed the pure photochemical nature of this etching process and allowed to improve considerably its reproducibility and reliability. Applying the HF treatment in combination with size-selective photoetching allows to vary the mean size of InP nanocrystals from ∼1.7 nm to 6.5 nm, resulting in monodisperse colloids with band-edge luminescence tunable from green to near-IR and room-temperature quantum yields in the range of 20−40%.