The development of narrowband emissive, bright, and stable solution-processed organic light-emitting diodes (SP-OLEDs) remains a challenge. Here, a strategy is presented that merges within a single emitter a TADF sensitizer responsible for exciton harvesting and an MR-TADF motif that provides bright and narrowband emission. This emitter design also shows strong resistance to aggregate formation and aggregation-cause quenching. It is based on a known MR-TADF emitter DtBuCzB with a donor-acceptor TADF moiety consisting of either tert-butylcarbazole donors (tBuCzCOHDCzB) or second-generation carbazole-based donor dendrons (2GtBuCzCOHDCzB) and a benzoate acceptor. The TADF moiety acts as an exciton harvesting antenna and transfers these excitons via Förster resonance energy transfer to the MR-TADF emissive core. The SP-OLEDs with 2GtBuCzCOHDCzB and tBuCzCOHDCzB thus show very high maximum external quantum efficiencies (EQE of 27.9 and 22.0%) and minimal efficiency roll-off out to 5000 cd m.
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http://dx.doi.org/10.1002/adma.202415289 | DOI Listing |
Predicting reaction barriers for arbitrary configurations based on only a limited set of density functional theory (DFT) calculations would render the design of catalysts or the simulation of reactions within complex materials highly efficient. We here propose Gaussian process regression (GPR) as a method of choice if DFT calculations are limited to hundreds or thousands of barrier calculations. For the case of hydrogen atom transfer in proteins, an important reaction in chemistry and biology, we obtain a mean absolute error of 3.
View Article and Find Full Text PDFRSC Adv
January 2025
Departamento de Física Aplicada, Facultade de Óptica e Optometríae Instituto de Materiais (iMATUS) Campus Vida, Universidade de Santiago de Compostela (USC) 15782 Galicia Spain.
The Cr and Sm doped GdAlO perovskite with formula GdSmAlCrO, was synthesized a solid-state reaction method, and its structure, morphology, and photoluminescence properties were thoroughly investigated. The compound crystallizes in the orthorhombic space group, with Cr transition-metal ions substituting Al in the octahedral symmetry site, and Sm lanthanide (rare-earth) ions occupying the tetrahedral site. The material's morphology and chemical composition homogeneity were evaluated through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Chemistry and Biochemistry and Centre for NanoScience Research, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada.
Three new analogues of Tb-UiO-66 with various functional groups (-F, -Br, -NH) on the terephthalic acid linker of the metal-organic framework (MOF) are synthesized and characterized. The photoluminescent properties of these analogues, as well as Tb-UiO-66 and Tb-UiO-66-(OH), are studied and correlated to the calculated energies for the triplet (T) states of each linker. The results show that the addition of electron withdrawing groups, such as -F and -Br, lead to higher T energies, resulting in quantum yields in the range of 6-31%.
View Article and Find Full Text PDFBiophys J
January 2025
Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom. Electronic address:
Photosynthetic organisms rely on a network of light-harvesting protein-pigment complexes to efficiently absorb sunlight and transfer excitation energy to reaction centre proteins where charge separation occurs. In photosynthetic purple bacteria, these complexes are embedded within the cell membrane, with lipid composition affecting complex clustering, thereby impacting inter-complex energy transfer. However, the impact of the lipid bilayer on intra-complex excitation dynamics is less understood.
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January 2025
Thermal and Energetic Systems Studies Laboratory (LESTE), LR99ES31, College of Engineering, University of Monastir, 5000, Monastir, Tunisia.
Using the RANS approach with the standard k-ω turbulence model, this study offers a novel investigation into the dynamic and thermal properties of turbulent impinging jet arrays. Our study examines the combined effect of the number of jets (N) and the jet-jet spacing (S) on flow mechanisms and heat transfer performance, which is unique compared to previous research that frequently focuses on the individual effects of parameters. Through the investigation of the turbulent kinetic energy, friction coefficient, velocity contours, streamlines, pressure contours, and local and mean Nusselt numbers, we provide important information about how these parameters impact flow dynamics.
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