Power conversion and luminous efficiency performance of nanophosphor quantum dots on color-conversion LEDs for high-quality general lighting

Date
2012
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Source Title
Proceedings of SPIE
Print ISSN
0277-786X
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Publisher
SPIE
Volume
8278
Issue
Pages
827811-1 - 827811-7
Language
English
Type
Conference Paper
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Abstract

For high-quality general lighting, a white light source is required to exhibit good photometric and colorimetric performance along with a high level of electrical efficiency. For example, a warm white shade is desirable for indoors, corresponding to correlated color temperatures ≥4000 K, together with color rendering indices ≥90. Additionally, the luminous efficacy of optical radiation (LER) should be high, preferably ≥380 lm/W opt. Conventional white LEDs cannot currently satisfy these requirements simultaneously. On the other hand, color-conversion white LEDs (WLEDs) integrated with quantum dots (QDs) can simultaneously reach such high levels of photometric and colorimetric performance. However, their electrical efficiency performance and limits have been unknown. To understand their potential of luminous efficiency (lm/Welect), we modeled and studied different QD-WLED architectures based on layered QD films and QD blends, all integrated on blue LED chips. The architecture of red, yellow and green emitting QD films (in this order from the chip outwards) is demonstrated to outperform the rest. In this case, for photometrically efficient spectra, the maximum achievable LE is predicted to be 327 lm/W elect. Using a state-of-the-art blue LED reported with a power conversion efficiency (PCE) of 81.3%, the overall WLED PCE is shown to be 69%. To achieve LEs of 100, 150 and 200 lm/Welect, the required minimum quantum efficiencies of the color-converting QDs are found to be 39, 58 and 79%, respectively. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

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Keywords
Quantum dot integrated white LEDs, Nanoluminophores, Power conversion efficiency, Luminous efficacy of optical radiation, Luminous efficiency, Color rendering index, Correlated color temperature, Photometry
Citation
Published Version (Please cite this version)