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The development of organic light-emitting diodes (OLED) with low efficiency roll-off at high brightness still remains a significant challenge. The hot-exciton mechanism provides a potential solution owing to its unique high-lying reverse intersystem crossing (hRISC) with a sufficiently large rate constant. Herein, two pyrene-based hot-exciton molecules, namely TPAPyCP and 2mTPAPyCP, were successfully designed using triphenylamine (TPA) as donor and benzonitrile as acceptor. The planar pyrene provided multiple fast hRISC channels, which effectively improved the photoluminescence quantum yield (PLQY) values to 73.2% and 65.8% in neat films. A non-doped device based on TPAPyCP demonstrated a maximum external quantum efficiency (EQE) of 9.41% and still maintained 8.95% at a high luminance of 10 000 cd m, highlighting a negligible efficiency roll-off of 4.97%.
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http://dx.doi.org/10.1039/d5sc01756d | DOI Listing |
RSC Adv
September 2025
Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC C/Sor Juana Inés de la Cruz, 3 Madrid 28049 Spain
Perovskite light-emitting diodes (PeLEDs) have emerged as a promising technology for next-generation display and lighting applications, thanks to their remarkable colour purity, tunability, and ease of fabrication. In this work, we explore the incorporation of plasmonic spherical nanoparticles (NPs) directly embedded into the green-emitting CsPbBr perovskite layer in a PeLED as a strategy to enhance both its optical and electrical properties. We find that plasmonic effects directly boost spontaneous emission while also influencing charge carrier recombination dynamics.
View Article and Find Full Text PDFNat Commun
September 2025
Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, China.
Perovskite quantum dot light-emitting diodes have rapidly achieved high external quantum efficiencies of over 25%; however, hindered by limited operating stability originating from surface defects or ion migration in quantum dots. Here, we design a lattice-matched anchoring molecule, tris(4-methoxyphenyl)phosphine oxide (TMeOPPO-p), to anchor the multi-site defects and stabilise the lattice. The target quantum dots exhibit high exciton recombination features with near-unity photoluminescence quantum yields (97%), and the as-fabricated quantum dot light-emitting diodes present a maximum external quantum efficiency of up to 27% at 693 nm, a low efficiency roll-off (over 20% at a current density of 100 mA cm for the typical device) and an operating half-life of over 23,000 h.
View Article and Find Full Text PDFChem Sci
August 2025
Key Laboratory of Theoretical and Computational Photochemistry of the Chinese Ministry of Education, College of Chemistry, Beijing Normal University Beijing 100875 P. R. China
As a class of functional materials used in organic light-emitting diodes (OLEDs), sensitizers play a crucial role in the improvement of device efficiency, color purity, and stability. In recent years, thermally activated delayed fluorescence (TADF) sensitizers have attracted much attention mainly because of their high exciton utilization efficiency by converting quenched triplet excitons into singlet excitons. Despite the experimental success of sensitization strategies in enhancing OLED performance, the lack of theoretical models for sensitizers continues to hinder further development.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2025
Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P.R. China.
The organic light-emitting diode (OLED) performance of multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters is fundamentally constrained by their slow reverse intersystem crossing (RISC) and pronounced aggregation-caused quenching (ACQ). Herein, through regioselective borylation, we design and synthesize a series of blue MR-TADF emitters. The regioisomerization-directed twist configuration synergistically enhances RISC while suppressing ACQ, without compromising spectral purity.
View Article and Find Full Text PDFChem Commun (Camb)
August 2025
Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
A simple-structure, pure-organic TADF sensitizer, namely, CFBOPXZ, targeting red hyperfluorescence was designed and synthesized. CFBOPXZ exhibits simultaneous high PLQY, rapid radiative decay and reverse intersystem crossing rates, enabling stable and narrowband red hyperfluorescent OLEDs with an external quantum efficiency of 40% and minimal efficiency roll-off.
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