Ultra-Efficient and High-Quality White Light-Emitting Devices using Fluorescent Proteins in Aqueous Medium

The transformation of electronics toward "green" and efficient devices is critical for the environmental sustainability and energy future. So far, majority of efficient lighting devices have been realized by artificial optical materials such as rare-earth-elements-doped phosphors, colloidal quantum dots (QDs) and dyes. In this study, red-emitting mScarlet and green-emitting eGFP fluorescent proteins are determined for high-performance white LEDs, expressed in living Escherichia coli and the purified proteins are integrated in their natural aqueous environment onto blue LED chips. The aqueous integration preserved quantum yield levels of the proteins above 70% in the device architecture and facilitated a high luminous efficiency (LE) of 81 lm W-1 with a color rendering index (CRI) of 83, which is the most efficient eco-friendly white LED reported to date. Moreover, the concentration ratio are also optimized of red- and green-emitting proteins and white protein-based LEDs with a maximum CRI of 92 are demonstrated. This study shows that fluorescent proteins hold great promise for the next generation eco-friendly, efficient and high-quality white light sources.