Cascade Synthesis of Luminescent Difluoroboron Diketonate Compounds for Room‐Temperature Organic Afterglow Materials

Advanced Optical Materials

et al. 2022

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Aqueous afterglow dispersions display promising biomedical applications due to their long‐lived excited states, whereas it is a common problem in the research field that processing and transferring solid‐state afterglow materials into aqueous medium can cause significant drop and even complete loss of their afterglow properties. Here, aqueous afterglow dispersions are fabricated from liquid precursors by dopant–matrix strategy and emulsion polymerization, which avoids the processing procedures on solid‐state materials and achieves 2.4 s long phosphorescence lifetimes in aqueous medium. Luminescent difluoroboron β‐diketonate dopants are first designed with small rate constant of phosphorescence decay and then dissolved in monomers. After emulsion polymerization, the as‐formed polymer latex particles not only assist dopants’ intersystem crossing but also provide a glassy microenvironment to largely suppress nonradiative decay of dopants’ triplets, leading to in situ formation of aqueous afterglow dispersions. This provides a robust method for constructing afterglow emulsions with long‐term colloidal stability, relatively high solid contents, tunable sizes, and diverse compositions. Through emulsion copolymerization, afterglow emulsions decorated with specific ligands are obtained to exhibit specific protein binding properties. Such decorated afterglow emulsions address the issue that afterglow materials lack biorecognition property and can pave the way for their applications in immunoassay and immunoimaging.

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confidence: 99%

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confidence: 99%

Organic Afterglow Emulsions Exhibiting 2.4 s Phosphorescence Lifetimes and Specific Protein Binding Property

Liu

Sun

Advanced Optical Materials

et al. 2022

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“…The fluoranthene‐containing BF 2 bdk compound, YNBF 2 , was synthesized via cascade reactions developed in our group [51–55] . This reaction is very simple, practical and straightforward, using the one‐pot reaction of fluoranthene, acetic anhydride and boron trifluoride diethyl etherate.…”

Section: Resultsmentioning

confidence: 99%

Manipulation of Organic Afterglow in Fluoranthene‐Containing Dopant‐Matrix Systems: From Conventional Room‐Temperature Phosphorescence to Efficient Red TADF‐Type Organic Afterglow

Yuan

et al. 2023

Chemistry A European J

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It remains challenging to fabricate highly-efficient and long-lived organic afterglow materials, especially in the case of red afterglow systems. Here we develop advanced charge transfer (CT) technology to boost afterglow efficiency and lifetimes in fluoranthene-containing dopant-matrix systems. First, organic CT molecules possess singlet-triplet splitting energy (ΔE ST ) of around 0.5 eV, much smaller than localized excitation systems. Second, upon doping into suitable organic matrices, dipole-dipole interactions between 1 CT states and organic matrices reduce 1 CT levels with less effect on 3 CT levels, and thus further narrow ΔE ST and enhance intersystem crossing. Third, the rigid planar structure of fluoranthene groups and the rigid microenvironment provided by organic matrices can suppress phosphorescence quenching. Forth, the multiple donor design enables spectral red-shifts to red region and switches on TADF mechanism to improve afterglow efficiency to 13.1 % and maintain afterglow lifetime of 0.1 s. Such high-performance afterglow materials have been rarely explored in reported studies.

“…On the other hand, two-component strategies have been found to allow a flexible choice of both organic matrices and luminescent dopants to construct RTP and organic afterglow materials with diverse compositions and structures. − ,,,− When one component (either dopants or matrices) is fixed, systematic studies by varying the other component lead to a deep understanding of the photophysical mechanism of dopant–matrix systems; this is very important for fabricating high-performance RTP and afterglow materials. There are representative studies for the fabrication of high-performance RTP and afterglow materials in two-component systems.…”

Section: Introductionmentioning

confidence: 99%

“…When the organic matrices are polymers, the dopant–matrix design strategy leads to the formation of polymer-based RTP and organic afterglow materials with excellent flexibility and mechanical properties. − Poly(methyl methacrylate) (PMMA) matrices have been mostly used because PMMA is inexpensive, transparent, and soluble in many organic solvents. Diverse PMMA-based RTP materials with anticounterfeiting and data encryption functions have been reported, and solution casting is the most applied technique to fabricate these materials. − Poly(vinyl alcohol) (PVA) matrices have been reported to provide a rigid microenvironment for and inhibit the nonradiative decay of triplet excited states of luminescent dopants, giving rise to intriguing color-tunable RTP systems and others. − Water processability is a unique advantage of PVA matrices different from other synthetic polymers. Polylactic acid (PLA)-based and end-capped systems have been reported to show film-forming properties and hypoxia sensing functions via fluorescence/phosphorescence dual emission behaviors. , Our recent studies showed that the macromolecular self-assembly strategy and photopolymerization technique can also be used to fabricate high-performance RTP materials. , Besides, polystyrene, polyacrylonitrile, poly(ethylene- co -vinyl acetate), and other polymers have been shown to suppress the nonradiative decay and quenching of luminescent dopants for constructing organic RTP materials. − Despite the diverse compositions of the above polymer-based materials, it is found that these materials mainly follow the RTP mechanism.…”

Section: Introductionmentioning

confidence: 99%

Polymer-Based TADF-Type Organic Afterglow

Huang

et al. 2022

J. Phys. Chem. C

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Polymer-based organic afterglow materials exhibit excellent flexibility and mechanical properties, whereas their afterglow mainly follows a phosphorescence mechanism with limited afterglow efficiency. Here, we report polymer-based TADFtype afterglow materials, which feature a moderate rate of reverse intersystem crossing of 1−10 s −1 to harvest triplet energies and consequently possess an afterglow efficiency of >80%. By doping a specific difluoroboron diketonate dye into polymer matrices, various polymer-based afterglow materials have been obtained. In particular, afterglow elastomers, which have been rarely reported, have also been achieved with a high efficiency of 50% and a long lifetime of 0.19 s. Variable temperature-delayed emission studies and TD-DFT calculations have been performed to support the TADF afterglow mechanism. This study would pave the way for highly efficient polymer-based organic afterglow materials and their promising applications in diverse areas.