Phase-transfer assisted synthesis of BiOI nanoplatelets, quantum-confined color and selective modification of surface conditioning

Nanoscale BiOI is prepared via a phase-transfer assisted reaction. To this concern, reaction of Bi(NO 3) 3·5H 2O and KI in water/2-propanol leads to the nucleation of BiOI. These nanoparticles are separated by an oleylamine-induced phase transfer to toluene. Colloidal stabilization of BiOI in the non-polar phase can be reversed by hydrazine-initiated removal of oleylamine. With glycine as a colloidal stabilizer the particles are redispersable in a polar phase such as water or alcohol. As-prepared BiOI is platelet-shaped with sizes of 200·200·18 nm and a specific surface of 16.0 m 2g −1. Due to one-dimensional size confinement, the color of the BiOI nanoplatelets – in contrast to carmine red bulk-BiOI ( E g: 1.83 eV) – is shifted to yellow ( E g: 2.00 eV). Based on its adaptable dispersibility and its color, BiOI nanoplatelets might be relevant as a color pigment as well as a semiconductor in solar cells. [Display omitted]