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PhD thesis on LEDs at Bilkent receives Innovation Award from Europe

Devices and Sensors Research Group, led by Assoc. Prof. Dr. Hilmi Volkan Demir from the Department of Electrical and Electronics Engineering, the Department of Physics, and UNAM – National Institute of Materials Science and Nanotechnology, has been working on the development and demonstration of high-quality light emitting diodes (LEDs) with superior photometric properties. As stated by the Photonics21 Strategic Research Agenda [1], LEDs based on quantum dots are required for high quality and efficient white light generation. From Demir's Group, Sedat Nizamoglu's PhD thesis on "Novel Semiconductor Quantum Dot Nanophosphors Integrated LEDs for High-Quality Lighting" received Photonics21 Student Innovation Award [2]. Sedat Nizamoglu is currently a PhD candidate at the Department of Electrical and Electronics Engineering and is working at UNAM. Photonics21 is a European Technology Platform funded with the support of European Commission to develop a coordinated strategy for the photonics community in Europe. Photonics21 is the high-level platform that brings together CEOs, CTOs, and R&D Heads of high-profile optics and photonics companies in Europe such as OSRAM, Philips, Carl Zeiss, Trumpf Laser, Cube Optics, and Ericsson, including all 27 member states of the European Union and 22 countries outside Europe. Demir Group has been recommended to be nominated for this innovation award by European Commission 7th Framework Nanophotonics4Energy Efficiency Network of Excellence in Europe, of which Demir Group is a Management Board Member and the principal investigator at Bilkent. Professor Demir's group is working on high efficiency light generation and light harvesting in this Network of Excellence, along with Network partners. In this project, Sedat Nizamoglu has achieved high color-rendering, warm white LEDs with high luminous efficacy using semiconductor quantum dots. This innovation award is intended to promote research with wide-scale impact in photonics. The winner of this award is selected on the basis of world-wide innovation and potential industrial impact. The award is sponsored by Thales, SPIE Europe and ACCORD Europe organizations Sedat’s PhD thesis work shows that nanocrystal integrated LED technology is superior in photometric properties than the current solid state lighting technologies in terms of color rendering index and luminous efficacy of optical radiation [3-5]. These experimental results indicate that the ongoing improvements of nanocrystals　synthesis can even further facilitate these light sources to achieve superior luminous efficiency, as also confirmed by recent computational studies [6].

[1] Second Strategic Research Agenda in Photonics (2010).

[2] http://www.photonics21.org/TrainingEducation/price_winner.php

[3] S. Nizamoglu, G. Zengin, and H. V. Demir, "Color-converting combinations of nanocrystal emitters for warm-white light generation with high color rendering index", Applied Physics Letters, 92, 031102 (2008).

[4] S. Nizamoglu, E. Mutlugun, T. Özel, H. V. Demir, S. Sapra, N. Gaponik, A. Eychmüller, "Dual-color emitting quantum-dot-quantum-well CdSe-ZnS heteronanocrystals hybridized on InGaN/GaN light emitting diodes for high-quality white light generation", Applied Physics Letters, 92, 113110 (2008).

[5] S. Nizamoglu, O. Akin, and H. V. Demir, "Quantum efficiency enhancement in nanocrystal solids using nanoradiative energy transfer with optimized donor-acceptor ratio for hybrid white light emitting diodes", Applied Physics Letters, 94, 243107 (2009).

[6] T.Erdem, S. Nizamoglu, X. W. Sun and H. V. Demir, " A photometric investigation of ultra-efficient LEDs with high color rendering index and high luminous efficacy employing nanocrystal quantum dot luminophores," Optics Express 18, 340-347 (2010).