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| Synthesis of size-selected, surface-passivated InP nanocrystals |
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| Author(s): Guzelian AA, Katari JEB, Kadavanich AV, Banin U, Hamad K, Juban E, Alivisatos AP, Wolters RH, Arnold CC, Heath JR |
| Source: JOURNAL OF PHYSICAL CHEMISTRY Volume: 100 Issue: 17 Pages: 7212-7219 Published: APR 25 1996 |
| Times Cited: 239 References: 32 |
| Abstract: Quantum-confined InP nanocrystals from 20 to 50 Angstrom in diameter have been synthesized via the reaction of InCl3 and P(Si(CH3)(3))(3) in trioctylphosphine oxide (TOPO) at elevated temperatures. The nanocrystals are highly crystalline, monodisperse, and soluble in various organic solvents. Improved size distributions have been obtained by size-selectively reprecipitating the nanocrystals. The UV/vis absorption spectra of the particles show the characteristic blue shift of the band gap of up to 1 eV due to quantum confinement, a moderately well-resolved first excitonic excited state, and, in some cases, the resolution of a higher excited state. Structurally, the nanocrystals are characterized with powder X-ray diffraction and transmission electron microscopy. Raman spectroscopy reveals TO and LO modes near the characteristic bulk InP positions as well. a surface mode resulting from finite size. The Raman line widths, line positions, and relative intensities are all size-dependent. X-ray photoelectron spectroscopy (XPS) shows the nanocrystals have a nearly stoichiometric ratio of indium to phosphorus with TOPO surface coverages ranging from 30% to 100%. We have also used XPS to correlate the oxidation of the nanocrystal surface with photoluminescence intensity. Photoluminescence is observed as both band edge and deep trap emission with both features shifting with nanocrystal size. The luminescence is highly dependent on the surface of the nanocrystal with oxidation being a necessary condition for emission. |
| Document Type: Article |
| Language: English |
Addresses:
1. UNIV CALIF BERKELEY, DEPT CHEM, BERKELEY, CA 94720 USA
2. LAWRENCE BERKELEY LAB, DIV MAT SCI, BERKELEY, CA 94720 USA
3. UNIV CALIF LOS ANGELES, DEPT CHEM & BIOCHEM, LOS ANGELES, CA 90095 USA |
| Publisher: AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 |
| Subject Category: Chemistry, Physical |
| IDS Number: UG823 |
| ISSN: 0022-3654 |
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