SYNTHESIS AND CHARACTERIZATION OF INP QUANTUM DOTS

Colloidal dispersions of quantum dots (QDs) of crystalline InP were sy nthesized starting from a chloroindium oxalate complex and P(SiMe(3))( 3). An InP precursor was formed from the reactants at room temperature ; heating the precursor in a solution of trioctylphosphine oxide at 27 0 degrees C for several days produced InP QDs with a mean diameter of 26.1 +/- 7.5 Angstrom (determined by counting lattice fringes in a TEM micrograph). From the known QD size distribution and its absorption s pectrum, we used a theoretical model to calculate the dependence of In P QD bandgap on QD size. From these results we could then calculate th e size distribution of any InP colloid from its absorption spectrum. I t was found that preparing the InP precursor with an excess of In3+ an d then heating it in a mixture of trioctylphosphine oxide and trioctyl phosphine at 270 degrees C for 3 days produced a very narrow QD size d istribution with a mean diameter of 25 +/- 1.9 Angstrom.