Here, we show the fabrication of the carbon dots (CDs) with green and orange emissions from PTCDA (perylene-3,4,9,10-tetracarboxylic dianhydride). Using these CDs as emitters, the orange (or green) CDs LEDs were fabricated, which show electroluminescence (EL) spectra centered at 560 nm (or 498 nm) with an external quantum efficiency (EQE) of 1.98 % (1.76 %) adhering a luminescence of 626 cd m (or 519 cd m ). The machine learning was successfully used to predict PL CCT value. With the model, the white photoluminescence (PL) emission with adjustable correlated color temperature (CCT) from 3093 to 11018 K via combining blue, green, and orange CDs was achieved. Then, we obtained the warm white CDs LEDs with CCT of 3107, 4071 and 4548 K, and cold white CDs LEDs with CCT of 5632 (CIE coordinates of (0.33, 0.33), EQE: 1.18 %, luminescence: 598 cd m ) and 6034 K accurately.
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http://dx.doi.org/10.1002/anie.202103086 | DOI Listing |
ACS Appl Mater Interfaces
December 2024
School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
Developing hybrid fluorescence (FL)/room-temperature phosphorescent (RTP) materials in dry-state, aqueous, and organic solvents holds paramount importance in broadening their applications. However, it is extremely challenging due to dissolved oxygen and solvent-assisted relaxation causing RTP quenching in an aqueous environment and great dependence on SiO-based materials. Herein, an efficient endogenetic carbon dot (CD) strategy within melamine-formaldehyde (MF) microspheres to activate RTP of CDs has been proposed through the pyrolysis of isophthalic acid (IPA) molecules and branched-chain intra-microspheres.
View Article and Find Full Text PDFNanoscale
December 2024
School of Energy, Soochow Institute for Energy and Materials InnovationS, Soochow University, Suzhou 215006, China.
Carbon dots (CDs) have attracted significant research interest due to their great potential in optoelectronic applications. Although various CDs have been synthesized the "bottom-up" pathway, few studies have focused on understanding the origins of the structural and optical diversities of CDs. In this study, two benzenoid acids with a slight structural variation (, 9-oxo-9-fluorene-2,7-dicarboxylic acid (FR) and 4,4'-biphenyl dicarboxylic acid (BP)) are employed as precursors, yielding orange- and red-emissive CDs with quantum yields of 43.
View Article and Find Full Text PDFNanoscale
December 2024
Department of Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Gent, Belgium.
Obtaining efficient blue emission from CdSe nanoplatelets (NPLs) remains challenging due to charge trapping and sub-bandgap emission. Thanks to a design-of-experiments (DoE) approach, we significantly improved the NPL synthesis, obtaining precise control over the lateral aspect ratio (length/width). We raised the photoluminescence quantum efficiency up to 66% after growth of a CdS crown, with complete elimination of trap-state emission.
View Article and Find Full Text PDFAdv Mater
November 2024
Yunnan Key Laboratory for Micro/Nano Materials & Technology, National Center for International Research on Photoelectric and Energy Materials, School of Materials and Energy, Yunnan University, Kunming, 650091, China.
The effective control over the self-assembly process of carbon dots (CDs) and their cluster luminescence in the aggregated state is of paramount significance and challenge. This study, for the first time, systematically explores the photoluminescent behavior of CDs in their aggregated state, which is less understood compared to their discrete state. By investigating the effects of concentration and solvent environment, it's demonstrated that CDs could exhibit dual emission properties, shifting from blue particle emissions to red cluster emissions as they aggregate.
View Article and Find Full Text PDFACS Appl Nano Mater
October 2024
Department of Physics and Bernal Institute, University of Limerick, Limerick V94 T9PX, Ireland.
High performance and high stability in all-inorganic solution processed nanocrystal-based light-emitting diodes (LEDs) are highly attractive for large area devices compared to organic material-based LEDs. In this work, an inverted all-inorganic LED structure is designed to have an easy integration with thin-film transistors. Adopting robust inorganic materials such as Ni O nanoparticle films as a hole transport layer (HTL) is beneficial for the performance of LED.
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