Colloidal synthesis of monodisperse luminescent InP nanocrystals

Luminescent InP nanocrystals were prepared by organometallic approaches using long chain alkylamines, trioctylphosphine and trioctylphosphine oxide as stabilizing and size regulating agents. The nanocrystals were characterized by powder XRD, synchrotron XPS, HRTEM, absorption and luminescence spectroscopy. Nearly monodisperse fractions of InP nanocrystals were isolated by the size-selective precipitation technique. As prepared, InP nanocrystals exhibit very poor photoluminescent properties, however, their PL efficiency can be drastically enhanced by photoetching of the nanoparticle surface with certain fluorine compounds. A new technique of controllable size-selective photoetching of colloidal nanoparticles allowed the preparation of nearly monodisperse fractions of InP nanocrystals with room temperature PL quantum yields of 25-40%. The PL band was tunable from green to near-IR with increasing particle size.