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An iminodibenzyl–quinoxaline–iminodibenzyl scaffold as a mechanochromic and dual emitter: donor and bridge effects on optical properties
摘要： The influence of phenyl linkage and donor strength on the photophysical properties of new derivatives of quinoxaline-containing iminodibenzyl and iminostilbene moieties is studied. The donor–acceptor derivatives showed dual thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) despite a large energy gap between the excited singlet and triplet states (ca. 0.5 eV). This extremely rare observation is explained by the twisted and rigidified structure of the iminodibenzyl moiety.
关键词： dual emitter,quinoxaline,room temperature phosphorescence,iminodibenzyl,optical properties,mechanochromic,bridge effects,thermally activated delayed fluorescence,donor
更新于2025-09-19 17:15:36
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Development of Light-Responsive Liquid Crystalline Elastomers to Assist Cardiac Contraction
摘要： Rationale: Despite major advances in cardiovascular medicine, heart disease remains a leading cause of death worldwide. However, the field of tissue engineering has been growing exponentially in the last decade and restoring heart functionality is now an affordable target; yet, new materials are still needed for effectively provide rapid and long-lasting interventions. Liquid Crystalline Elastomers (LCEs) are biocompatible polymers able to reversibly change shape in response to a given stimulus, and generate movement. Once stimulated, LCEs can produce tension or movement like a muscle. However, so far their application in biology was limited by a slow response time and a modest possibility to modulate tension levels during activation. Objective: To develop suitable LCE-based materials to assist cardiac contraction. Methods and Results: Thanks to a quick, simple and versatile synthetic approach, a palette of biocompatible acrylate-based light-responsive LCEs with different molecular composition was prepared and mechanically characterized. Out of this, the more compliant one was selected. This material was able to contract for some weeks when activated with very low light intensity within a physiological environment. Its contraction was modulated in terms of light intensity, stimulation frequency and ton/toff ratio to fit different contraction amplitude/time courses, including those of the human heart. Finally, LCE strips were mounted in parallel with cardiac trabeculae, and we demonstrated their ability to improve muscular systolic function, with no impact on diastolic properties. Conclusions: Our results indicated LCEs are promising in assisting cardiac mechanical function and developing a new generation of contraction assist devices.
关键词： physiology.,muscle contraction,cardiac tissue engineering,mechanics,light-activated materials,mechanical characterization,Artificial cardiac muscles,liquid crystalline elastomers,muscle disease
更新于2025-09-19 17:15:36
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Rational design, synthesis, and characterization of a photocrosslinkable hole-transporting polymer for high performance solution-processed thermally activated delayed fluorescence OLEDs
摘要： A new photocrosslinkable hole-transporting homopolymer (PX2Cz) was successfully synthesized using 9-((3-methyloxetan-3-yl)methyl)-90-(4-vinylbenzyl)-9H,90H-3,30-bicarbazole monomer via radical polymerization. Biscarbazole, as a hole-transporting material, has two reactive sites that can introduce a radical polymerizable styrene moiety and a photocrosslinkable oxetane moiety. The photocuring temperature and time for the PX2Cz film was optimized to be 120 1C and 10 s. The photocured films showed good solvent resistance, which is favorable for the deposition of an emitting-layer solution on them. In particular, the highest occupied molecular orbital (HOMO) energy of the as-cast PX2Cz film was determined to be (cid:2)5.37 eV which remained unchanged even after photocuring, thus facilitating hole transportation from the hole-injection layer. Subsequently, solution-processed, green, thermally activated delayed fluorescent organic light-emitting diodes (TADF-OLEDs) were manufactured using PX2Cz as the hole-transport material. The devices displayed a notable performance with an exceptionally low turn-on voltage (Von) of only 2.8 V and a high external quantum e?ciency (EQE) of 22.5%; these values are substantially better than those of commonly used poly(9-vinylcarbazole) (PVK)-based OLEDs (Von = 3.6 V, EQE of 15.5%). The remarkably low turn-on voltage and high EQE were ascribed to the shallower HOMO energy level and more pronounced hole-transport ability of the photocured PX2Cz film.
关键词： OLEDs,photocrosslinkable,hole-transporting polymer,solution-processed,thermally activated delayed fluorescence
更新于2025-09-19 17:13:59
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Phenothiazine dioxide-containing derivatives as efficient hosts for blue, green and yellow thermally activated delayed fluorescence OLEDs
摘要： By conjugating 10-phenyl-10H-phenothiazine-5,5-dioxide (2PTO) with aromatic amine substituents (PhCz and DMACMN), three novel host materials namely 10-(9-phenyl-9H-carbazol-3-yl)-10H-phenothiazine 5,5-dioxide (3CzNPTO), (10-(4-(9H-carbazol-9-yl)phenyl)-10H-phenothiazine 5,5-dioxide (9CzNPTO) and 10-(4-(9,9-dimethylacridin-10(9H)-yl)-2,5-dimethylphenyl)-10H-phenothiazine 5,5-dioxide (DMACMNPTO) were designed and synthesized. DMACMNPTO with thermally activated delayed fluorescence (TADF) feature exhibited the bipolar characteristic resulting from the completely separated HOMO/LUMO distribution. Using DMACMNPTO as a host for TADF emitters, the devices showed a maximum external quantum efficiencies (EQEmax), current e?ciency (CEmax) and power e?ciency (PEmax) of 18.3%, 33.3 cd/A and 37.4 lm/W in the blue-emitting diode, 18.6%, 49.1 cd/A and 47.2 lm/W in the green-emitting diode, and 19.1%, 59.2 cd/A and 66.0 lm/W in the yellow-emitting diode, respectively. These results corroborated the potential of phenothiazine dioxide-containing derivatives as host materials in a sequence of colors TADF-OLEDs.
关键词： phenothiazine dioxide,Organic light-emitting devices,thermally activated delayed fluorescence,host
更新于2025-09-19 17:13:59
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Photocatalytic degradation of gaseous toluene using self-assembled air filter based on chitosan/activated carbon/TiO2
摘要： Photocatalytic filters are integrated with air purifiers and ventilation systems to remove volatile organic compounds (VOCs) from indoor air. However, the filters, generally prepared by dip or spray coating, are less stable as the deposited TiO2 NPs are prone to be blown off by treated air. In the present study, we propose a novel filter preparation method based on self-assembly of activated carbon (AC) and TiO2 on non-woven polyethylene terephthalate (PET) fabric using chitosan (CS). The prepared filter (CSAT-PET) was characterized for morphological and chemical properties which revealed the homogeneity and chemical bonding of deposited TiO2. Photocatalytic activity of the prepared filter was evaluated for toluene degradation (200–600 ppb) under dark and UV illumination. Toluene removal efficiency reached 91% over CSAT-PET, while it was only 62% over pure TiO2 filter. About 40% of toluene removal was achieved by adsorption on CSAT-PET. Furthermore, CSAT-PET showed robust performance for selected face velocity ranging from 0.5 to 1.5 m/s and, the reaction rate followed Langmuir-Hinshelwood model. FTIR study identified benzaldehyde and benzoic acid as adsorbed intermediates. A UV-induced filter regeneration partially released the adsorbed species. CSAT-PET showed consistent toluene removal and intact morphology over five degradation cycles. The Box-Behnken design (BBD) in RSM was applied to optimize the filter preparation method. The optimum values of TiO2, AC and CS loading were 38.3 g/m2, 52.6 g/m2 and 2.06% (w/v), respectively which exhibited highest removal efficiency for toluene (93%). The proposed methodology can be adapted to fabricate low-cost, stable, and reusable photocatalytic filter for air purification applications.
关键词： Volatile organic compounds,Air filter,Photocatalytic oxidation,Titanium dioxide,Activated carbon,Self-assembly
更新于2025-09-19 17:13:59
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Highly Efficient Cyan-Green Emission in Self-Activated Rb <sub/>3</sub> RV <sub/>2</sub> O <sub/>8</sub> (R = Y, Lu) Vanadate Phosphors for Full-Spectrum White Light-Emitting Diodes (LEDs)
摘要： Phosphor-converted white-light-emitting diodes (pc-WLEDs) rely on combining a near-ultraviolet (n-UV) or blue chip with trichromatic and yellow-emitting phosphors. It is challenging to discover cyan-green-emitting (480?520 nm) phosphors for compensating the spectral gap and producing full-spectrum white light. In this work, we successfully discovered two unprecedented bright cyan-green emitting Rb3RV2O8 (R = Y, Lu) phosphors that gives emission bands centered at 500 nm upon 362 nm n-UV light excitation. Interestingly, the both self-activated compounds exhibit high internal quantum e?ciencies (IQEs) of 71% for Rb3YV2O8 and 85% for Rb3LuV2O8, respectively. Moreover, controllable emission color can be successfully tuned from cyan-green to orange-red across the warm white light region by design strategy of VO4 3? → Eu3+ energy transfer. The thermal quenching of as-prepared phosphors could be e?ectively mitigated by this design strategy. Finally, the as-fabricated n-UV (λ ex = 370 nm) pumped phosphor-converted (pc) W-LED devices utilizing Rb3RV2O8 (R = Y, Lu) along with commercial phosphors demonstrate well-distributed warm white light with high color-rendering index (CRI) of 91.9 and 93.5, and a low correlated color temperature (CCT) of 5095 and 4946 K. It suggests that the both vanadate phosphors have potential applications in full-spectrum pc-WLEDs.
关键词： cyan-green emission,self-activated,full-spectrum white light-emitting diodes,energy transfer,vanadate phosphors
更新于2025-09-19 17:13:59
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Thermally Activated Delayed Fluorescence Benzyl Cellulose Derivatives for Nondoped Organic Light-Emitting Diodes
摘要： Thermally activated delayed ?uorescence (TADF) benzyl cellulose derivatives (TBC-X), which contained both carbazole (host) and phthalimide-based TADF dye (guest) moieties, were prepared from 2,3-di-O-benzyl cellulose in high yields. The TBC-X samples were soluble in common organic solvents such as CH2Cl2, CHCl3, THF, and toluene. The photoluminescence spectra of TBC-X spin-coated ?lms had a single emission peak derived only from guest moieties, which indicated e?cient energy transfer from the host to guest moieties. The TBC-10 (with a content of host and guest moieties of 93 and 7, respectively) in a spin-coated ?lm had the highest photoluminescence quantum yield of 55.3% and TADF characteristics. A nondoped organic light-emitting diode with TBC-10 as the emitting layer showed green emission (λ EL = 517 nm) and achieved a maximum external quantum e?ciency of 5.9%.
关键词： Thermally activated delayed ?uorescence,TADF,organic light-emitting diodes,benzyl cellulose derivatives,OLEDs
更新于2025-09-19 17:13:59
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Improved luminescence properties of a novel red dodec-fluoride phosphor Ba <sub/>3</sub> Sc <sub/>2</sub> F <sub/>12</sub> :Mn <sup>4+</sup> with extraordinary thermal stability for WLED application
摘要： Mn4+-activated red phosphors have recently attracted tremendous attention for their fascinating performance in white light emitting diodes (WLEDs) application to achieve warm white light, while the thermal stability of fluoride is still considered as a drawback. Herein, we report a novel red phosphor composed of Ba3Sc2F12:Mn4+ (BSF:Mn), in which, the emitting centers of Mn4+ ions are locating in the sites of Sc3+ ions. The photoluminescence of BSF:Mn varies with the concentration of K2MnF6, reaction temperature, and the concentrations of NH3·H2O in reaction system. Partly substituting Ba2+ with Ca2+ decreases the luminescent intensity of BSF:Mn. By employing the as-prepared phosphor BSF:Mn as a red component, a high-performance WLED with a correlated color temperature (CCT) at 4796 K and a color rendering index (CRI) of 85.2 was obtained. The phosphor BSF:Mn keeps undecomposed up to 800 oC, therefore, this work exhibits a strategy to explore a novel Mn4+-doped fluoride with particularly thermal stability.
关键词： luminescent properties,thermal stability,Ba3Sc2F12:Mn4+,Mn4+-activated red phosphors,WLEDs
更新于2025-09-19 17:13:59
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5H-Benzo[d]Benzo[4,5]Imidazo[2,1-b][1,3]Thiazine as a Novel Electron-Acceptor Cored High Triplet Energy Bipolar Host Material for Efficient Solution-Processable Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes
摘要： Organic entities that can transport electrons are seldom available to develop adequate bipolar host materials applicable for solution-processable thermally activated delayed ?uorescence (TADF)-organic light-emitting diodes (OLEDs). Therefore, the introduction of new electron-af?ne entities that plausibly demonstrate high triplet energy (ET) is of urgent need. In this contribution, we introduced benzimidazo[1,2-a][3,1]benzothiazine (BBIT) as a novel electron-af?ne entity and developed two new bipolar host materials, CzBBIT and 2CzBBIT. Both host materials exhibit high ET of 3.0 eV, superior thermal robustness with the thermal decomposition temperature of up to 392?C, a glass transition temperature of up to 161?C, and high solubility in common organic solvents. Consequently, the solution-processable OLEDs fabricated using a recognized IAcTr-out as the green TADF emitter doped into CzBBIT as the host, realized a maximum external quantum ef?ciency (EQE) of 23.3%, while the 2CzBBIT:IAcTr-out blend ?lm-based device displayed an EQE of 18.7%. These outcomes corroborated that this work could shed light on the scienti?c community on the design of new electron-af?ne entities to establish the effective use of bipolar host materials toward pro?cient solution-processable TADF-OLEDs.
关键词： bipolar hosts,new electron-acceptor core,thermally activated delayed ?uorescence,organic light emitting diodes,solution process
更新于2025-09-19 17:13:59
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Yellow/Orange-Emitting ABZn2Ga2O7:Bi3+ (A = Ca, Sr; B = Ba, Sr) Phosphors: Optical Temperature Sensing and WLED Applications
摘要： Recently, there is growing interest in developing Bi3+-activated luminescence materials for optoelectronic applications. Herein, new yellow/orange-emitting ABZn2Ga2O7:Bi3+ (ABZGO, A = Ca, Sr; B = Ba, Sr) phosphors with tunable optical properties are synthesized by alkaline earth cation substitution. When Sr2+ substitutes Ca2+ and Ba2+, the excitation wavelength has a red shift from 325 to 363 nm, matching well with the n-UV chips based WLEDs. CaBaZn2Ga2O7:0.01Bi3+ (CBZGO:0.01Bi3+) exhibits two evident emission peaks at 570 and 393 nm originating from the respective occupation of Ca and Ba sites by Bi3+ ions. The optical tuning of CBZGO:Bi3+ phosphor is achieved by changing Bi3+ doping content and excitation wavelength based on the selected site occupation. Differently, both SrBaZn2Ga2O7:0.01Bi3+ (SBZGO:0.01Bi3+) and Sr2Zn2Ga2O7:0.01Bi3+ (SZGO:0.01Bi3+) phosphors exhibit a single broad emission band, peaking at 600 and 577 nm, respectively. Two different Bi3+ sites are also verified respectively in SBZGO and SZGO hosts by the Gaussian fitting of the asymmetric PL spectra and lifetime analysis. The different luminescence behaviors of ABZGO:0.01Bi3+ phosphors should be ascribed to the synergistic effect of centroid shift, crystal-field splitting and Stokes shift. Moreover, the temperature-dependent PL spectra reveal that cation substitutions of Sr2+ for Ca2+ and Ba2+ can efficiently improve the thermal stability of ABZGO:0.01Bi3+ phosphors. In view of different thermal responses to various temperature for two emission peaks of CBZGO:0.01Bi3+ phosphor, an optical thermometer is designed and has a good relative sensitivity (Sr = 1.453% K-1) at 298 K. Finally, a WLED with CRI = 97.9 and CCT = 3932 K is obtained by combining SZGO:0.01Bi3+ and BAM:Eu2+ phosphors with a 370 nm n-UV chip, demonstrating that SZGO:0.01Bi3+ is an excellent yellow-orange-emitting phosphor for n-UV WLED devices. This work stimulates the exploration of optical tuning by cation substitution to obtain remarkable luminescence materials for optical temperature sensing and WLED applications.
关键词： optical temperature sensing,WLED applications,optical tuning,Bi3+-activated,thermal stability,luminescence materials
更新于2025-09-19 17:13:59