Fully Biogenic Near‐Infrared Phosphors: Phycobiliproteins and Cellulose at Force Toward Highly Efficient and Stable Bio‐Hybrid Light‐Emitting Diodes.

Stable/efficient low‐energy emitters for photon down‐conversion in bio‐hybrid light‐emitting diodes (Bio‐HLEDs) are still challenging, as the archetypal fluorescent protein (FP) mCherry has led to the best deep‐red Bio‐HLEDs with poor stabilities: 3 h (on‐chip)/160 h (remote). Capitalizing on the excellent refolding under temperature/pH/chemical stress, high brightness, and high compatibility with polysaccharides of phycobiliproteins (smURFP), first‐class low‐energy emitting Bio‐HLEDs are achieved. They outperform those with mCherry regardless of using reference polyethylene oxide (on‐chip: 24 h vs. 3 h) and new biopolymer hydroxypropyl cellulose (HPC; on‐chip: 44 h vs. 3 h) coatings. Fine optimization of smURFP‐HPC‐coatings leads to stable record devices (on‐chip: 2600 h/108 days) compared to champion devices with perylene diimides (on‐chip: <700 h) and artificial FPs (on‐chip: 35 h). Finally, spectroscopy/computational/thermal assays confirm that device degradation is related to the photo‐induced reduction of biliverdin to bilirubin. Overall, this study pinpoints a new family of biogenic emitters toward superior protein‐based lighting. [ABSTRACT FROM AUTHOR]