We have developed a two-phosphine strategy to independently tune nucleation and growth kinetics based on the relative reactivity of each precursor in the synthesis of indium phosphide (InP) quantum dots (QDs). This approach was allowed by the exploration of the synthesis and reactivity of a series of sterically encumbered triarylsilylphosphines substituted at the para position of the aryl group, P(Si(C 6 H 4 -X) 3 ) 3 (X = H, Me, CF 3 , or Cl), as a contrast to P(SiMe 3 ) 3 , the P 3− source commonly employed in such syntheses. UV−vis absorption spectroscopy of aliquots taken during InP QD growth revealed a stark contrast between triarylsilylphosphines with electron-donating and electron-withdrawing groups in both the rate of InP formation and the final particle size. 31 P{ 1 H} nuclear magnetic resonance spectroscopy confirmed that precursor conversion remains rate-limiting throughout the nanocrystal synthesis when P(SiPh 3 ) 3 is incorporated as the sole phosphorus precursor; however, this is insufficient for effective separation of nucleation and growth in this system because of the slow nucleation rates that result. In all cases, syntheses that employ a single chemical species as the P 3− source were found to suffer from a poor match in reactivity with In(O 2 C(CH 2 ) 12 CH 3 ) 3 as they either fail to separate nucleation from growth because of slow precursor conversion rates [P(SiPh 3 ) 3 and P(Si(C 6 H 4 -Me) 3 ) 3 ] or preclude size selective growth from rapid precursor conversion [P(SiMe 3 ) 3 , P(Si(C 6 H 4 -Cl) 3 ) 3 , and P(Si(C 6 H 4 -CF 3 ) 3 ) 3 ]. To balance these two extreme cases, we developed a novel approach in which two different P 3− sources were introduced to segregate nucleation and growth based on the relative reactivity of each precursor.

The synthesis and characterization of crystalline colloidal zinc phosphide quantum dots with observable excitonic transitions ranging between 424-535 nm (2.3-2.9 eV) are reported. A ternary combination of ZnEt2, Zn(O2CR)2, and P(SiMe3)3, forms a pentanuclear zinc cluster on mixing followed by conversion to (Et2Zn)P(ZnO2CR)2(SiMe3) in a rate-determining step prior to quantum dot formation.

The effects of precursor solution concentration, composition, and spin-processing parameters on the thickness and electrical properties of ultra-smooth aluminum oxide phosphate (Al 2 O 3-3x (PO 4 ) 2x or -AlPO‖) thin films prepared using aqueous solutions are reported. Compositions were verified by electron probe micro-analysis and range from Al 2 O 1.5 (PO 4 ) to AlPO 4 (x = P:Al from 0.5-1.0). Film thicknesses were determined using X-ray reflectivity measurements and were found to depend systematically on solution concentration, P:Al ratio, and spin-speed.Metal-insulator-semiconductor devices were fabricated to determine electrical properties as a function of composition. As the P:Al ratio increased from 0.5 to 1.0, the dielectric constant decreased from 6.0 to 4.6, leakage currents increased from 0.45 to 65 nA cm -2 at 1MV cm -1 and dielectric breakdown (defined as leakage currents >10 µA cm -2 ) decreased from 9.74 to 2.84 MV cm -1 . These results establish composition, concentration, and spin-speed for the production of AlPO films with targeted thicknesses and electrical properties.