High Color-Rendering Index and Stable White Light-Emitting Diodes by Assembling Two Broadband Emissive Self-Trapped Excitons.
basic_science · Level V
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- Record sourced from PubMed, PMID 33225543.
- Also identified by DOI 10.1002/adma.202001367.
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Abstract
White light-emitting diodes (WLEDs) are promising next-generation solid-state light sources. However, the commercialization route for WLED production suffers from challenges in terms of insufficient color-rendering index (CRI), color instability, and incorporation of rare-earth elements. Herein, a new two-component strategy is developed by assembling two broadband emissive materials with self-trapped excitons (STEs) for high CRI and stable WLEDs. The strategy addresses effectively the challenging issues facing current WLEDs. Based on first-principles thermodynamic calculations, copper-based ternary halides composites, CsCu<sub>2</sub> I<sub>3</sub> @Cs<sub>3</sub> Cu<sub>2</sub> I<sub>5</sub> , are synthesized by a facile one-step solution approach. The composites exhibit an ideal white-light emission with a cold/warm white-light tuning and a robust stability against heat, ultraviolet light, and environmental oxygen/moisture. A series of cold/warm tunable WLEDs is demonstrated with a maximum luminance of 145 cd m<sup>-2</sup> and an external quantum efficiency of 0.15%, and a record high CRI of 91.6 is achieved, which is the highest value for lead-free WLEDs. Importantly, the fabricated device demonstrates an excellent operation stability in a continuous current mode, exhibiting a long half-lifetime of 238.5 min. The results promise the use of the hybrids of STEs-derived broadband emissive materials for high-performance WLEDs.