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Open Access Nano Express

Photoluminescence enhancement in CdS quantum dots by thermal annealing

Jae Ik Kim, Jongmin Kim, Junhee Lee, Dae-Ryong Jung, Hoechang Kim, Hongsik Choi, Sungjun Lee, Sujin Byun, Suji Kang and Byungwoo Park*

Author Affiliations

WCU Hybrid Materials Program, Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744, South Korea

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Nanoscale Research Letters 2012, 7:482  doi:10.1186/1556-276X-7-482

Published: 29 August 2012

Abstract

The photoluminescence behavior of CdS quantum dots in initial growth stage was studied in connection with an annealing process. Compared to the as-synthesized CdS quantum dots (quantum efficiency ≅ 1%), the heat-treated sample showed enhanced luminescence properties (quantum efficiency ≅ 29%) with a narrow band-edge emission. The simple annealing process diminished the accumulated defect states within the nanoparticles and thereby reduced the nonradiative recombination, which was confirmed by diffraction, absorption, and time-resolved photoluminescence. Consequently, the highly luminescent and defect-free nanoparticles were obtained by a facile and straightforward process.

Keywords:
CdS quantum dot; photoluminescence; quantum efficiency; local strain; relaxation