2015年 第76回応用物理学会秋季学術講演会

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13 半導体 » 13.9 光物性・発光デバイス

[13p-PA6-1~17] 13.9 光物性・発光デバイス

2015年9月13日(日) 16:00 〜 18:00 PA6 (イベントホール)

16:00 〜 18:00

[13p-PA6-3] Enhanced Brightness of White Light Emission from Wide-Band-Gap Materials Sensitized by Narrow-Band-Gap Quantum Dots

〇(P)Satish Shinde1,2, Hari Krishna Sadhanala1, Duy Thang2, Tadaaki Nagao2, Karuna Kar Nanda1 (1.IISc, India, 2.NIMS, Japan)

キーワード:White light emission,Wide band gap,Quantum dots

Phosphors are of paramount importance for a variety of applications including white light emitting diodes (LEDs), solar cells, bio-imaging, etc.1 Several promising strategies and materials have been explored to generate bright white light.2 For the generation of white light, wide-band-gap (WBG) materials are shown to be advantageous as the band gap depends very weakly on the size of the nanostructures.2 Though WBG materials emit light in the entire visible region, the brightness emission is limited by various defect levels.1,2
Here, we demonstrate enhanced brightness from WBG GeO2 sensitized by narrow-band-gap (NBG) CdTe quantum dots. Both experimental and theoretical approaches used to understand the underlying mechanism of enhanced brightness from WBG materials. Interestingly, WBG materials act as acceptors, while NBG quantum dots act as donors. The efficiency of enhanced brightness follows an exponential behavior with the band gap energy of donors and acceptors. One of the major implications is the designing of wide band gap materials as bright white light emitting phosphors that convert the ultraviolet into visible light efficiently. Over all, the brightness can be enhanced by combining the two extreme band gap materials.
References
1. H. -Q. Wang, M. Batentschuk, A. Osvet, L. Pinna, and C. J. Bra: Adv. Mater. 23 (2011) 2675.
2. E. F. Schubert and J. K. Kim: Science 308 (2005) 1274.