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Protein-integrated white light-emitting diodes for efficient, high-quality and biocompatible solid-state lighting

Final Report Summary - PROTEINLED (Protein-integrated white light-emitting diodes for efficient, high-quality and biocompatible solid-state lighting)

Green photonics aims to provide solutions that generate or save energy, reduce pollution and greenhouse gas emissions, produce environmentally sustainable outputs or enhance public health. Solid-state lighting (SSL), one of the most important green photonics technologies, offers 50% reduction in global electricity consumption for lighting that corresponds to the production by hundreds of coal plants and decrease in millions of tons of carbon emission, if the entire conventional white light sources are to be replaced with energy-efficient light emitting diodes (LEDs). However, the widely used phosphor-based white LED technology and the currently investigated nanocrystal-based white LEDs have limitations in terms of biocompatibility, energy efficiency and color quality. To this end, we proposed a new class of color-conversion LEDs integrated with proteins to overcome the disadvantages of currently used and investigated color conversion materials.

For this, we worked on the theoretical modeling, design, fabrication and experimental realization of these new solid-state lighting devices. As a result, we achieved the ultimate goal of the protein-integrated white LEDs. We showed warm, daylight and cool white LEDs using biologically-derived fluorescent proteins for general lighting. We demonstrated that the optimized expression and purification of fluorescent proteins allow for chip-scale integration of proteins and white light generation. Advantageously, the combinations of different protein emitters enable sensitive tuning of photometric quantities for application-specific lighting sources. Color rendering index (CRI) and luminous efficacy of optical radiation (LER) are two important metrics used to characterize white light LEDs. The cool white LED exhibits a CRI value of 83, which satisfies the color rendering index for future solid state lighting applications, while achieving a high luminous efficacy of 291 lm/W. Therefore, the fluorescent protein integrated white LEDs show promise for efficient and high-quality lighting.

Moreover, we showed the use fluorescent proteins for display applications. The usage time of displays (e.g. TVs, mobile phones, etc) is in general shorter than their functional life time, which worsens the electronic waste (e-waste) problem around the world. The integration of biomaterials into electronics can help to reduce the e-waste problem. In this study, we demonstrated fluorescent protein integrated white LEDs to use as a backlight source for liquid crystal (LC) displays for the first time. We expressed and purified enhanced green fluorescent protein (eGFP) and monomeric Cherry protein (mCherry), and afterward we integrate these proteins as a wavelength-converter on a blue LED chip. The protein-integrated backlight exhibits a high luminous efficacy of 248 lm/Wopt and the area of the gamut covers 80% of the NTSC color gamut. The resultant colors and objects in the image on the display can be well observed and distinguished. Therefore, fluorescent proteins show promise for display applications.

Furthermore, one of the important technical challenges in thermal packaging is to ensure a better thermal conductivity than 0.2 W/m-K of current materials for most of the traditional silicone polymers in SSL applications. We investigated an unconventional material of the silk fibroin proteins for LED package encapsulation, and showed that this biomaterial provides thermal advantages leading to an order of magnitude higher thermal performance than conventional silicones. Silk fibroin is a natural protein and directly extracted from silk cocoons produced by Bombyx mori silkworm. Therefore, it presents a “green” material for photonic applications with its superior properties of biocompatibility and high optical transparency with a minimal absorption. Combining these properties with high thermal performance makes this biomaterial promising for future LED applications.

In the scope of this project, so far Dr. Nizamoglu published one international journal paper entitled “Fluorescent Protein Integrated White LEDs for Displays” in Nanotechnology by IOP (Nanotechnology 27, 45LT01 (2016)) and one national journal publication, presented 2 reviewed conference paper organized by OSA and ASME ( & and presented more than 5 invited talks, and applied for 2 patents. Moreover, another paper on silk-hydrogel lenses is under review and one other on the modelling of light-protein interactions is currently under preparation.

After joining the European Research Area he published two more papers in Nature Communication (S. Nizamoglu et. al., “Bioabsorbable polymer optical waveguides for deep-tissue photomedicine,” Nature Communications 7, 10374 (2016)) and Advanced Optical Materials (S. Nizamoglu et. al., “A Simple Approach to Biological Single-Cell Lasers Via Intracellular Dyes” Advanced Optical Materials 3, 1197–1200 (2015).) that he acknowledged the Marie Curie Career Integration Grant (CIG). Moreover, his Nature paper is selected as Image of the Week by Nature Communication and moreover it is featured in a new TV series ‘White Rabbit Project’ in Netflix, Episode 8. During the project phase, in 2014 he was recognized as Innovator Under 35 by the world’s oldest and most respected technology publication “MIT Technology Review”.

The Marie Curie CIG grant has been so far a crucial facilitator in Dr. Nizamoglu’s reintegration that significantly improved his research potential, and he proved this potential by receiving a European Research Council’s (ERC) Starting Grant (NOVELNOBI, 639846) . These achievements promoted him to have a long-term position at Koc University and established his interdisciplinary research group combining engineering, science and medicine. His team currently consists of 2 postdoctoral research fellows and 6 graduate (MS & PhD) students now.