Issue 17, 2014

Correlation between native defects and dopants in colloidal lanthanide-doped Ga2O3 nanocrystals: a path to enhance functionality and control optical properties

Abstract

We report the synthesis and study of the photoluminescence properties of colloidal lanthanide(III)-doped Ga2O3 nanocrystals. The Ga2O3 nanocrystal host lattice acts as a sensitizer of the Eu3+ dopant red emission arising from intra-4f orbital transitions, and concurrently exhibits a strong blue photoluminescence originating from defect-based donor–acceptor pair (DAP) recombination. The Eu3+ sensitization, enabled by the energy transfer from the nanocrystal host lattice to the dopant centers, allows for the generation of dual blue-red emission. Increasing doping concentration leads to a decrease in the donor activation energy allowing for simultaneous control of the optical and electrical properties of these multifunctional nanocrystals. Analyses of the steady-state and time-resolved photoluminescence spectra suggest that Eu3+ ions occupy at least two different sites, which were tentatively designated as the six-coordinate internal and surface-related dopants. Uniquely, both DAP and Eu3+ emissions have long lifetimes (in milliseconds), although Eu3+ luminescence has a slower decay rate. These phenomena enable a temporal modulation of the dual emission and photoluminescence chromaticity on the millisecond timescale. The generality of these findings was demonstrated by preparing Tb3+-doped Ga2O3 nanocrystals, as a blue-green dual emitter. Owing to their optical transparency, electrical properties, emission color versatility, robustness, and fabricability, colloidal lanthanide(III)-doped Ga2O3 nanocrystals are a promising class of multifunctional materials and complex phosphors.

Graphical abstract: Correlation between native defects and dopants in colloidal lanthanide-doped Ga2O3 nanocrystals: a path to enhance functionality and control optical properties

Supplementary files

Article information

Article type
Paper
Submitted
14 Sep 2013
Accepted
22 Oct 2013
First published
15 Nov 2013

J. Mater. Chem. C, 2014,2, 3212-3222

Correlation between native defects and dopants in colloidal lanthanide-doped Ga2O3 nanocrystals: a path to enhance functionality and control optical properties

T. Wang, A. Layek, I. D. Hosein, V. Chirmanov and P. V. Radovanovic, J. Mater. Chem. C, 2014, 2, 3212 DOI: 10.1039/C3TC31823K

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