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Electroluminescent Warm White Light-Emitting Diodes Based on Passivation Enabled Bright Red Bandgap Emission Carbon Quantum Dots.
- Source :
-
Advanced science (Weinheim, Baden-Wurttemberg, Germany) [Adv Sci (Weinh)] 2019 Apr 30; Vol. 6 (13), pp. 1900397. Date of Electronic Publication: 2019 Apr 30 (Print Publication: 2019). - Publication Year :
- 2019
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Abstract
- The development of efficient red bandgap emission carbon quantum dots (CQDs) for realizing high-performance electroluminescent warm white light-emitting diodes (warm-WLEDs) represents a grand challenge. Here, the synthesis of three red-emissive electron-donating group passivated CQDs (R-EGP-CQDs): R-EGP-CQDs-NMe <subscript>2</subscript> , -NEt <subscript>2</subscript> , and -NPr <subscript>2</subscript> is reported. The R-EGP-CQDs, well soluble in common organic solvents, display bright red bandgap emission at 637, 642, and 645 nm, respectively, reaching the highest photoluminescence quantum yield (QY) up to 86.0% in ethanol. Theoretical investigations reveal that the red bandgap emission originates from the rigid π-conjugated skeleton structure, and the -NMe <subscript>2</subscript> , -NEt <subscript>2</subscript> , and -NPr <subscript>2</subscript> passivation plays a key role in inducing charge transfer excited state in the π-conjugated structure to afford the high QY. Solution-processed electroluminescent warm-WLEDs based on the R-EGP-CQDs-NMe <subscript>2</subscript> , -NEt <subscript>2</subscript> , and -NPr <subscript>2</subscript> display voltage-stable warm white spectra with a maximum luminance of 5248-5909 cd m <superscript>-2</superscript> and a current efficiency of 3.65-3.85 cd A <superscript>-1</superscript> . The warm-WLEDs also show good long-term operational stability ( L / L <subscript>0</subscript> > 80% after 50 h operation, L <subscript>0</subscript> : 1000 cd m <superscript>-2</superscript> ). The electron-donating group passivation strategy opens a new avenue to realizing efficient red bandgap emission CQDs and developing high-performance electroluminescent warm-WLEDs.<br />Competing Interests: The authors declare no conflict of interest.
Details
- Language :
- English
- ISSN :
- 2198-3844
- Volume :
- 6
- Issue :
- 13
- Database :
- MEDLINE
- Journal :
- Advanced science (Weinheim, Baden-Wurttemberg, Germany)
- Publication Type :
- Academic Journal
- Accession number :
- 31380189
- Full Text :
- https://doi.org/10.1002/advs.201900397