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Proceedings Paper

Power conversion and luminous efficiency performance of nanophosphor quantum dots on color-conversion LEDs for high-quality general lighting
Author(s): Talha Erdem; Sedat Nizamoglu; Hilmi Volkan Demir
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Paper 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/Wopt. 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/Welect. 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.

Paper Details

Date Published: 6 February 2012
PDF: 7 pages
Proc. SPIE 8278, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XVI, 827811 (6 February 2012); doi: 10.1117/12.907468
Show Author Affiliations
Talha Erdem, Bilkent Univ. (Turkey)
Sedat Nizamoglu, Bilkent Univ. (Turkey)
Hilmi Volkan Demir, Bilkent Univ. (Turkey)
Nanyang Technological Univ. (Singapore)


Published in SPIE Proceedings Vol. 8278:
Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XVI
Klaus P. Streubel; Heonsu Jeon; Li-Wei Tu; Norbert Linder, Editor(s)

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