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Cell-Penetrating Peptides Transport Noncovalently Linked Thermally Activated Delayed Fluorescence Nanoparticles for Time-Resolved Luminescence Imaging
摘要： Luminescent probes and nanoparticles (NPs) with long excited state lifetimes are essential for time-resolved biological imaging. Generally, cell membranes are physiological barriers that could prevent the uptake of many unnatural compounds. It is still a big challenge to prepare biocompatible imaging agents with high cytomembrane permeability, especially for nonmetallic NPs with long-lived luminescence. Herein, an amphiphilic cell-penetrating peptide, F6G6(rR)3R2, was designed to transport hydrophobic fluorophores across cellular barriers. Three classical thermally activated delayed fluorescence (TADF) molecules, 4CzIPN, NAI-DPAC, and BTZ-DMAC, could self-assemble into well-dispersed NPs with F6G6(rR)3R2 in aqueous solution. These NPs showed low cytotoxicity and could penetrate membranes easily. Moreover, long-lived TADF enabled them to be used in time-resolved luminescence imaging in oxygenic environments. These findings greatly expanded the applications of cell-penetrating peptides for delivery of molecules and NPs by only noncovalent interactions, which were more flexible and easier than covalent modifications.
关键词： cell-penetrating peptide,Luminescent probes,time-resolved biological imaging,nanoparticles,noncovalent interactions,thermally activated delayed fluorescence
更新于2025-09-04 15:30:14
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High Performance Thermally Activated Delayed Fluorescence Sensitized Organic Light‐Emitting Diodes
摘要： Recently, organic light-emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) materials have aroused huge attention in both academia and industry. Compared with fluorescent and phosphorescent materials, TADF materials can theoretically capture 100 % excitons without incorporating noble metals, making them effective emitters and hosts for OLEDs simultaneously. Here, in this review, our recent works on mechanisms and materials of high performance TADF-sensitized phosphorescent (TSP) OLEDs, TADF-sensitized fluorescent (TSF) OLEDs and TADF-sensitized TADF (TST) OLEDs are summarized. Finally, we propose the outlook for the further development and application of TADF-sensitized OLEDs.
关键词： bipolar host,Dexter energy transfer,organic light-emitting diodes,F?rster energy transfer,thermally activated delayed fluorescence
更新于2025-09-04 15:30:14
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Experimental Evidence for “Hot Exciton” Thermally Activated Delayed Fluorescence Emitters
摘要： Contradiction between no effective photophysical experiments and high device results causes the “hot exciton” thermally activated delayed fluorescence (TADF) mechanism to be still a controversial question. Here, the steady and transient photophysical characterization combined with theoretical calculation based on 4,7-bis(9,9-dimethyl-9H-fluoren-2-yl)-5,6-difluorobenzo[c][1,2,5]thiadiazole (2F-BTH-DMF), 4,7-bis(9,9-dimethyl-9H-fluoren-2-yl)benzo[c][1,2,5]thiadiazole (BTH-DMF), and 5,6-bis(9,9-dimethyl-9H-fluoren-2-yl)benzo[c][1,2,5] thiadiazole (o-BTH-DMF) demonstrate that all the emitters exhibit TADF via reverse intersystem crossing (RISC) from “hot exciton” triplet excited state. The fast RISC process “hot exciton” mechanism affords a very short delayed lifetime (1 μs). Organic light-emitting diodes (OLEDs) based on these emitters exhibit high exciton utilization over 25% and the best device shows a maximum current efficiency of 31.02 cd A?1, maximum power efficiency of 27.85 lm W?1, and external quantum efficiency of 9.13%, which are the highest performances for reported OLEDs with “hot exciton” mechanism. The experimental evidence for fast RISC process via “hot exciton” triplet state and short delayed lifetime highlights the TADF emitters with “hot exciton” mechanism for high-performance OLEDs with very low efficiency roll-off.
关键词： hot excitons,reverse intersystem crossing,thermally activated delayed fluorescence,organic light-emitting devices
更新于2025-09-04 15:30:14