Bioinspired Hybrid White Light‐Emitting Diodes

Abstract

The first bioinspired hybrid white-light-emitting diodes (bio-HLEDs) featuring protein cascade coatings are presented. For easy fabrication a new strategy to stabilize proteins in rubber-like material was developed. The synergy between the excellent features of fluorescent proteins and the easily processed rubber produces bio-HLEDs with less than 10% loss in luminous efficiency over 100 hours.

Easy and versatile coating approach for long-living white hybrid light-emitting diodes

“…S1 (ESI †). Similar to water-based gels, 8 the viscous properties of the acetonitrilebased gels allow an excellent handling for coating purposes. Indeed, the viscosity can be controlled by modifying the amount of the l-PEO - Fig.…”

“…2, branched and linear poly(ethylene oxide) compounds (b-and l-PEO, respectively) in different mass ratios -was optimized to form gels and rubber materials after mixing them with fluorescent proteins diluted in an aqueous media. 8 Without the addition of water, neither the gel nor the rubber are formed. This could limit the versatility of this concept, as only compounds soluble in water could be applied.…”

“…On one hand, we demonstrate the ease of preparation and application of luminescent rubbers for down-converting lighting schemes. Here, important assets of our approach are (i) the in situ preparation of the rubbers without using any cross-linking and UV-or thermal-curing methods, and (ii) its versatility in terms of using any kind of luminescent materials, such as fluorescent proteins, 8 small-molecules, carbon quantum dots, polymers, and coordination complexes. Here, we have ensured that the amount of the compounds is kept constant, but a further enhancement of the luminous efficiency should be possible if the concentration of the compounds is increased, as it will reduce the coating thickness.…”

“…1 As an alternative, recent research has explored the possibility of using eco-friendly organic down-converting materials in the so-called white hybrid inorganic/organic LEDs (WHLEDs). [5][6][7][8] Similar to WLEDs, the architecture of WHLEDs consists of a standard inorganic blue-or UV-LED, in which the encapsulation system is replaced by an organic-based down-converting material, which upon continuous excitation features a broad low-energy emission band - Fig. 1 and 2.…”

“…This architecture has recently led to WHLEDs with high colour quality -i.e., commission international de l'Éclairage (CIE) coordinates of 0.30-3/0.30-3, colour rendering index (CRI) above 90, and correlated colour temperature (CCT) between 2500-6500 K, but still with low stabilities of around 100 h due to degradation of the luminescent material, the matrix, or both upon continuous excitation under ambient conditions. [5][6][7][8] Up to date, there are four different approaches to develop down-converting coatings. Firstly, thin films, which consist of a mixture of organic materials with UV-or thermal-curable sealing reagents, are typically deposited either onto a glass substrate or on top of the packing of the LED - Fig.…”