Red fluorescent siloles with aggregation-enhanced emission characteristics

A series of new red fluorescent siloles consisting of a silole core and dimesitylboranyl substituent connected with a furan, thiophene, and selenophene bridges were synthesized and characterized. The optical properties, electronic structures, and electroluminescence （EL） performances were investigated. The emission wavelengths were red-shifted from the siloles with furan, to those with thiophene, and then selenophene. The thiophene, and selenophene-containing siloles, （MesB）2DTTPS, and （MesB）zDSTPS, showed the typical aggregation-enhanced emission （AEE） feature, while furan-containing one, （MesB）2DFTPS, showed slight emission decrease as the aggregate formation. Theoretical calculations were carried out to explain the difference in the optical properties. Undoped OLEDs using these red siloles as light-emitting layers were fabricated. The device of （MesB）2DTTPS exhibited the best performance. It radiated red EL emission at 589 nm, and afforded good maximum luminance, current, power, and external quantum efficiency of 13300 cd m^-2, 4.3 cd A^-1, 2.9 lm W^-1, and 1.8%, respectively.

An efficient aggregation-enhanced delayed fluorescence luminogen created with spiro donors and carbonyl acceptor for applications as an emitter and sensitizer in high-performance organic light-emitting diodes

Organic light-emitting diodes(OLEDs)fabricated using organic thermally activated delayed fluorescence materials as sensitizers have recently achieved significant advancements,but the serious efficiency roll-offs are still troublesome in most cases.Herein,a tailor-made multifunctional luminogen SBF-BP-SFAC containing 9,9′-spirobifluorene(SBF)and spiro[acridine-9,9-fluorene](SFAC)as electron donors and carbonyl as an electron acceptor is synthesized and characterized.SBF-BPSFAC has the advantages of high thermal stability,aggregation-enhanced delayed fluorescence,and balanced carrier transport ability,and prefers horizontal dipole orientation.Highly efficient OLEDs employing SBF-BP-SFAC as an emitter radiate intense cyan light with outstanding external quantum efficiencies(ηexts)of up to 30.6%.SBF-BP-SFAC can also serve as an excellent sensitizer for orange fluorescence,phosphorescence,and delayed fluorescence materials,providing excellent η exts of up to 30.3% with very small efficiency roll-offs due to the fast Förster energy transfer as well as exciton annihilation suppression by bulky spiro donors.These outstanding performances demonstrate the great potential of SBF-BP-SFAC as an emitter and sensitizer for OLEDs.

An AEE-active Polymer Containing Tetraphenylethene and 9,10-Distyrylanthracene Moieties with Remarkable Mechanochromism

A polymer （poly（9,10）anthracenevinylene-alt-4,4＇-（9,9-bis（4-（4＇-（1,2,2＇-triphenyviny）phenoxy）butyl）-9H- fluorene-2,7-diyl） dibenzaldehyde）, P1） was successfully synthesized through the Wittig-Horner reaction by employing fluorene and 9,10-distyrylanthracene moieties as building blocks for backbone and tetraphenylethenes as pendant groups. Photophysical and thermal properties of the resulting polymeric emitter were fully characterized by ultraviolet-visible （UV- Vis） absorption and photoluminescence （PL） spectra, thermogravimetric analysis （TGA） and differential scanning calorimetry （DSC）. While P1 emits an orange-light centered at 567 nm in dilute tetrahydrofuran （THF） solution, the solid powder of the polymer exhibits strong yellow emission peaked at 541 nm. It is also found that the as-synthesized polymer shows unique property of aggregation-enhanced emission （AEE）. In addition, P1 possesses high thermal stability with a decomposition temperature （Td,5%） of 430 ℃ and high morphological stability with a glass transition temperature （Tg） of 171℃. Under the stimulus of mechanical force, the emission of P1 can be changed from yellow to red （△λmax = 61 rim）, showing a remarkable mechanochromism. The results from XRD analysis suggest that such mechanochromic phenomenonof PI is probably caused by the destruction of crystalline structure, which leads to the conformational planarization of the distyrylanthracene moieties forming by the polymerization and the increase of molecular conjugation of the backbone.

Polymerizable AEE-active Dye with Optical Activity for Fluorescent Nanoparticles Based on Phenothiazine:Synthesis,Self-assembly and Biological Imaging

In consideration of various advantages such as less harm,higher sensitivity,and deeper imaging depth,etc.,AIE materials with longwave emission are attracting extensive attention in the fields of vascular visualization,organelle imaging,cells tracker,forensic detection,bioprobe and chemosensor,etc.In this work,a novel fluorescent(R)-PVHMA monomer with chirality and aggregation-induced emission enhancement(AEE)characteristics was acquired through enzymatic transesterification reaction basing on phenothiazine,and its[α]D25℃value was about-6.39°with a 3.08 eV bandgap calculated by the quantum calculations.Afterwards,a series of PEG-PVH1 and PEG-PVH2 copolymers with chirality feature were achieved through RAFT polymerization of the obtained(R)-PVHMA and PEGMA with various feed ratios.When the feed molar ratio of(R)-PVHMA increased from 21.5%to 29.6%,its actual molar fractions in the PEG-PVH1 and PEG-PVH2 copolymers accordingly increased from 18.1%to 25.7%.The molecular weight of PEG-PVH1 was about 2.2×10^(4) with a narrow PDI,and their kinetics estimation showed a first-order quasilinear procedure.In aqueous solution,the amphiphilic copolymers PEG-PVH could self-assemble into about 100 nm nanoparticles.In a 90%water solution of H_(2)O and THF mixture,the fluorescence intensity had the maximum value,and the emission wavelength presented at 580 and 630 nm.The investigation of cytotoxicity and cells uptake showed that PEG-PVH FONs performed outstanding biocompatibility and excellent cells absorption effects,which have great potential in bioimaging application.

具有聚集荧光增强效应的四苯基吡嗪类衍生物的制备和性能研究

聚集诱导发光(AIE)已经成为光物理和发光材料领域的研究热点.设计与合成新的AIE核心分子是该领域进一步发展的基础.在我们发展的、新的AIE核心分子四苯基吡嗪(TPP)的基础上,通过引入给电子的噻吩基团,设计合成了三个TPP的衍生物TPP-T、TPP-2T和T-TPP-T,并详细研究了三个分子的构效关系.结果表明三个分子均具有聚集荧光增强(AEE)效应,其粉末的最强发射峰分别位于418,437和436 nm处,属于蓝紫光和深蓝光发射,绝对荧光量子产率分别为26.8%,29.%和30.9%.结合其优异的热稳定性,这些TPP衍生物有望用于有机发光二极管(OLED)器件中的发光层.

荧蒽修饰的四苯基乙烯衍生物:分子合成、聚集增强荧光特性及其对苦味酸的高灵敏度检测

由于聚集体和固态发光量子效率高等优点,因此聚集诱导发光(AIE)材料成为光电功能材料研究领域的热点,拓展AIE分子体系始终是这一领域中的关键和基础的科学问题.通过Suzuki-Miyaura偶联这一条件较为温和的反应,将AIE生色团四苯基乙烯(TPE)与荧蒽直接共轭键接,制备得到单荧蒽和双荧蒽修饰的TPE衍生物TPE-FA与TPE-DFA,它们具有聚集增强荧光(AEE)行为,聚集体发射峰值波长分别在477和494 nm,固体薄膜的绝对荧光量子产率高达74.1%和40.4%.它们可以高灵敏地检测苦味酸,荧光猝灭常数大,检出限低于1μg·g^(-1).这两种AEE分子可望用于其它多硝基取代的芳香类吸电子分子的检测.

A Silole-Based Efficient Electroluminescent Material with Good Electron-Transporting Potential

A new silole derivative, 2,5-bis（7-（dimesitylboranyl）-9,9-dimethylfluoren-2-yl）- 1 -methyl- 1,3,4-triphenylsilole （（MesBF）2MTPS）, is synthesized and characterized. （MesBF）2MTPS shows a good fluorescence efficiency of 15% in THF solution and a higher efficiency of 86% in solid film, presenting an aggregation-enhanced emission charac- teristic. It is thermally and morphologically stable, with high decomposition and glass-transition temperatures of 257 and 171 ℃, respectively. The LUMO energy level （-2.96 eV） of （MesBF）zMTPS is lower than that of TPBi, revealing its electron-transporting potential. Efficient organic light-emitting diodes （OLEDs） are fabricated using （MesBF）2MTPS as emitter, which radiates yellow light at 554 nm, and affords high maximum luminance, current efficiency, and external quantum efficiency of 48348 cd·m^-2, 12.3 cd·A^-1, and 4.1%, respectively.

Deciphering Benzene-Heterocycle Stacking Interaction Impact on the Electronic Structures and Photophysical Properties of Tetraphenylethene-Cored Foldamers

Conjugation,as an essential chemical term used to describe electron delocalization,can be roughly grouped into two categories,through-bond conjugation(TBC)and through-space conjugation(TSC).A hybrid conjugation system integrating both TBC and TSC is rarely studied and utilized,for lack of a well-established model and difficulty of structure modification and property tuning,despite its theoretical significance and potential applications.Herein,various foldamers with a tetraphenylethene(TPE)core are employed as hybrid conjugation models to investigate structure–property correlation by introducing heterocycles of furan/thiophene into theπ-stacking TSC component.For comparison,two kinds of TPE-cored foldamers with different stacking models,a benzene–heterocycle stacking model and a benzene–benzene stacking model,are designed.Combining experimental measurements and theoretical calculations,the impact of benzene–heterocycle interaction on the hybrid conjugation natures and photophysical properties has been studied systematically.The results reveal that the benzene–heterocycle stacking model can fabricate a hybrid conjugation nature with an improved TSC component to make a more dominant contribution to the electronic transition natures than the benzene–benzene stacking model,leading to the distinguishing photophysical behavior.This work provides valuable guidance for the design of new functional materials with hybrid conjugation systems.

Recent advances of folded tetraphenylethene derivatives featuring through-space conjugation

Through-space conjugated molecules are interesting building blocks for the construction of functional materials that allow multi-dimensional transport of carrier and energy.However,the well explored through-space conjugated molecules are quite limited,which defers their structure-property correlation establishment and wide-scale application.In this review,we introduce a kind of newly-emerging folded tetraphenylethene derivatives featuring through-space conjugation.Their synthesis,crystal and electronic structures,and optical properties are described,and their representative applications as bipolar charge-transporting materials in organic light-emitting diodes and as single-molecule wires in molecular devices are presented,which are anticipated to provide guidance for the further expansion of through-space conjugated systems.

Boronic acid-containing carbon dots array for sensitive identification of glycoproteins and cancer cells

Discrimination of glycoproteins and cell types is a significant but difficult issue.Herein,we presented a novel fluorescence sensor array for the detection and identification of glycoproteins and cancer cells based on the specific affinity between boronic acid-containing carbon dots(BA-CDs)and cis-diol residues of polysaccharides.The differential binding affinity of three BA-CDs to various glycoproteins resulted in a different fluorescence turn-on signal pattern caused by aggregation-enhanced emission(AEE),along with negligible response from other proteins.Therefore,BA-CDs encompassing sensing elements and signal indicator into one can enable a fast and accurate discrimination of glycoproteins with simple and easy operation.Seven glycoproteins could be well discriminated at a very low concentration of 10 nmol/L.The discriminating capability of glycoproteins is not sacrificed in both human urine and serum.Notably,different glycoprotein compositions of cancer cells provide more recognizable features for identification of cancer cells,comparing to the total protein.Five cell types could be identified in 15 min at a low concentration of 1000 cells/mL.This method is fast,accurate,and easy operation,and has a potential application in cancer diagnosis.