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BCl3-Activated Synthesis of COO-BODIPY Laser Dyes: General Scope and High Yields under Mild Conditions
摘要： A general and straightforward method for the synthesis of COO-BODIPYs from F-BODIPYs and carboxylic acids is established. The method is based on the use of boron trichloride to activate the involved substitution of fluorine, which leads to high yields through rapid reactions under soft conditions. This mild method opens the way to unprecedented laser dyes with outstanding efficiencies and photostabilities, which are difficult to obtain by the current methods.
关键词： COO-BODIPY,Laser Dyes,Mild Conditions,High Yields,BCl3-Activated Synthesis
更新于2025-09-19 17:13:59
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Angular-Fused Dithianaphthylquinone Derivative: Selective Synthesis, Thermally Activated Delayed Fluorescence Property, and Application in Organic Light-Emitting Diode
摘要： A novel angular-fused dithianaphthylquinone derivative, f-TX-TPA, was designed and selectively synthesized. The regioselectivity of angular-fused reaction was interpreted by theoretical calculations. The f-TX-TPA compound displayed excellent thermally activated delayed ?uorescence property. Moreover, the organic light-emitting diodes (OLEDs) using f-TX-TPA as an emitter exhibited a high external quantum e?ciency of 15.9%. These results indicated that angular-fused dithianaphthylquinone derivatives could have great potential in the application of high-e?ciency OLEDs.
关键词： thermally activated delayed ?uorescence,organic light-emitting diode,angular-fused dithianaphthylquinone,high-e?ciency
更新于2025-09-19 17:13:59
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Calix[4]resorcinarene-based Hyper-Structured Molecular Thermally Activated Delayed Fluorescence Yellow-Green Emitters for Non-doped OLEDs
摘要： A novel hyper-structured molecular (HSM) thermally activated delayed fluorescent (TADF) emitters, in which the TADF units and host units are bound together into one inactive core through the flexible linkage, was designed. Phenoxazine-triphenyltriazine (PXZ-Trz), 1,3-bis(9H-carbazol-9-yl)benzene (mCP) and calix[4]resorcinarene (CRA) were chosed as TADF unit, host unit and core, respectively, a series of CRA-based HSM emitter, CRA-PXZ-Trz(X)-mCP(100-X). (x=0, 12.5, 25, 50, 75, 87.5 or 100) were succesfully synthesized by a two-step click reaction. Using non-doped CRA-PXZ-Trz(87.5)-mCP(12.5) as the light-emitting layer, the solotion-precessable OLEDs emitted yellow-green light, and dispiayed a external quantum efficiency of 16.7% at 100 cd/m2.
关键词： Thermally activated delayed fluorescence,Solution-processable,Non-doped OLEDs,Calix[4]resorcinarene,Hyper-structured molecular
更新于2025-09-19 17:13:59
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Enhanced bonding strength of InP/Si chip-on-wafer by plasma-activated bonding using stress-controlled interlayer
摘要： This study demonstrates high-yield InP/Si CoW plasma-activated bonding using a chip holder with pockets, the depth of which is precisely controlled. Additionally, finite element simulations are used to determine that the stress-controlled interlayer consisting of InP-based epitaxial layers with tensile strain effectively suppresses stress at the InP/Si bonding interface, which affects the bonding strength. Thus, a high bonding strength of 20 MPa in 2 mm × 2 mm InP chips on the Si substrate was achieved by introducing a superlattice structure consisting of GaInAsP and InP (with tensile strain) as the stress-controlled interlayer.
关键词： chip-on-wafer,plasma-activated bonding,bonding strength,InP/Si,stress-controlled interlayer
更新于2025-09-19 17:13:59
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Structural isomers of 9-(pyridin-2-yl)-9H-carbazole in combination with 9a?2H-9,3':6a?2,9a?3-tercarbazole and their application to high efficiency solution processed green TADF OLEDs
摘要： Two host materials, CzPy2TCz and CzPy3TCz, were designed as structural isomers and synthesized to achieve high efficiency thermally activated delayed fluorescence-organic light emitting diodes (TADF-OLEDs). The design strategy involved introducing a pyridine group into the core structure as an electron-withdrawing unit and varying the substitution position of tercarbazole (TCz). To realize green TADF-OLED, the two host materials synthesized in this study have excellent thermal stability and high excited triplet energy (T1 ? 2.95–2.98 eV). The maximum external quantum efficiency and current efficiency values for CzPy2TCz were 23.81% and 80.2 cd/A, respectively and the respective values for CzPy3TCz were 20.27% and 70.1 cd/A, respectively. Structural isomers with carbazole (Cz) and TCz units at the 2,6-position of the pyridine core effectuate better device performance. Consequently, we found that the host materials introduced in this study play an important role in implementing high performing solution-processed green TADF-OLED.
关键词： Thermally activated delayed fluorescence,Organic light-emitting diode,Tercarbazole,Pyridine,Host material,Solution process
更新于2025-09-19 17:13:59
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Photodynamic activation of irrigation (using different laser prototypes) on push out bond strength of fiber posts
摘要： Background: To evaluate the influence of photodynamic therapy (PDT) and light activated irrigation (LAI) using different laser prototypes Er,Cr:YSGG (ECYL), Er:Yag (EYL), Nd-Yag (NYL) on pushout bond strength of Pre-fabricated fiber reinforced composite (PFRC) post to radicular dentin. Material and method: Fifty maxillary and mandibular teeth were collected, cleaned and decoronated. Canals were instrumented using crown-down technique. Flaring of canals was performed using protaper S1, SX files. F1, F2 and F3 files were utilized for finishing of canal preparations. Prepared root canals were dried and obturated with gutta percha. Teeth were placed vertically within the section of polyvinyl pipes using acrylic resin. Post space preparation was completed using peso-reamers. Based on the PDT and laser activated irrigation (LAI) with different laser prototypes, samples were divided into five groups of 10 specimens each. Group 1- PDT, group 2–5.25 % NaOCl (sodium hypochlorite) and 17 % EDTA (ethylene diamine tetra acetic acid), group 3–5.25 % NaOCl with 17 % EDTA and NYL, group 4–5.25 % NaOCl with 17 % EDTA and EYL ; and group 5–5.25 % NaOCl +17 % EDTA and ECYL. Fiber post were luted in root canals with self-etch dual cure cement and teeth were sectioned at three levels (apical, middle and coronal). Push-out test was performed by placing the specimens in universal testing machine. Failure analysis of debonded surfaces was evaluated using stereomicroscope at 40× magnification. Means and standard deviations of push out bond strength were assessed by one-way analysis of variance (ANOVA). Comparison between means of push out bond strength was evaluated using Tukey multiple comparison tests (p = 0.05). Result: The highest push out bond strength was observed in group 5 at all three levels, coronal (10.08 ± 0.74 MPa), middle (8.95 ± 0.94 MPa) and apical (6.00 ± 0.88 MPa). The lowest push out bond strength was demonstrated by group 2 at all levels, coronal (6.15 ± 1.22 MPa), middle (5.65 ± 0.95 MPa) and apical (2.25 ± 0.55 MPa). Intra-group comparison showed decrease in push out bond strength in the coronal to apical direction among all investigated groups. Inter-group comparison exhibited comparable push out bond strength at all three levels of root for group 1 and group 2 specimens (p > 0.05). Conclusion: LAI with different laser prototypes improved push out bond values of PFRC post to root dentin as an adjunct to NaOCl and EDTA treatment. PDT improved push out strength compared to conventional canal cleaning regime.
关键词： Light activated irrigation,Bond failure,Photodynamic therapy,Push out bond strength,Laser prototypes
更新于2025-09-19 17:13:59
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Facile generation of thermally activated delayed fluorescence and fabrication of highly efficient non‐doped OLEDs based on triazine derivatives
摘要： A series of donor-acceptor-donor triazine-based molecules with thermally activated delayed fluorescence (TADF) properties were synthesized to obtain highly efficient blue-emitting OLEDs with non-doped emitting layer (EML). The targeted molecules use a triazine core as the electron acceptor, and a benzene ring as the conjugated linker with different electron donors to alternate the energy level of HOMO to further tune the emission color. The introduction of long alkyl chains on the triazine core inhibits the unwanted intermolecular D-D/A-A type π-π interactions, resulting in the intermolecular D-A charge transfer. The weak aggregation-caused quenching (ACQ) effect caused by the suppressed intermolecular D-D/A-A type π-π interaction further enhances the emission. The crowded molecular structure allows the electron donor and acceptor to be nearly orthogonal, thereby reducing the energy gap between triplet and singlet excited states (ΔEST). As a result, blue-emitting devices with TH-2DMAC and TH-2DPAC non-doped EML showed satisfactory efficiencies of 12.8% and 15.8%, respectively, which is one of the highest EQEs reported in the blue TADF emitters (λpeak < 475 nm), demonstrating that our tailored molecular designs are promising strategies to endow OLEDs with excellent EL performances.
关键词： triazine derivatives,non-doped emitting layer,OLEDs,blue-emitting,thermally activated delayed fluorescence,TADF
更新于2025-09-19 17:13:59
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Nanosecond-time-scale delayed fluorescence molecule for deep-blue OLEDs with small efficiency rolloff
摘要： Aromatic organic deep-blue emitters that exhibit thermally activated delayed fluorescence (TADF) can harvest all excitons in electrically generated singlets and triplets as light emission. However, blue TADF emitters generally have long exciton lifetimes, leading to severe efficiency decrease, i.e., rolloff, at high current density and luminance by exciton annihilations in organic light-emitting diodes (OLEDs). Here, we report a deep-blue TADF emitter employing simple molecular design, in which an activation energy as well as spin–orbit coupling between excited states with different spin multiplicities, were simultaneously controlled. An extremely fast exciton lifetime of 750 ns was realized in a donor–acceptor-type molecular structure without heavy metal elements. An OLED utilizing this TADF emitter displayed deep-blue electroluminescence (EL) with CIE chromaticity coordinates of (0.14, 0.18) and a high maximum EL quantum efficiency of 20.7%. Further, the high maximum efficiency were retained to be 20.2% and 17.4% even at high luminance.
关键词： deep-blue OLEDs,organic light-emitting diodes (OLEDs),small efficiency rolloff,Nanosecond-time-scale delayed fluorescence,thermally activated delayed fluorescence (TADF)
更新于2025-09-19 17:13:59
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Recent advances in thermally activated delayed fluorescence for white OLEDs applications
摘要： Thermally activated delayed fluorescence (TADF) materials, which can harvest all excitons without utilizing any noble metals to emit light, are becoming the key cornerstone for developing the next generation of organic light-emitting diode (OLED) devices. In recent years, TADF materials are attracting numerous attentions as a new surge of research focuses on both science and industry owing to their high efficiency, low power consumption, and low production cost attributes when applied to white OLEDs. The design and application of TADF in WOLED devices have also experienced the rapid development in fundamental science and industrial technology perspectives. In the present review, the specific reverse intersystem crossing mechanism and evolution of TADF is outlined firstly, and then the latest research progress of TADF-WOLEDs is summarized and discussed. TADF/conventional fluorescence, TADF/phosphorescence, all TADF and TADF exciplex-based WOLEDs are categorized and elaborated in terms of the device structure, working mechanism, efficiency, color-rendering index, etc. Finally, we conclude with the future challenges and opportunities in high-quality TADF devices and application area.
关键词： Thermally activated delayed fluorescence,exciplex,OLED,TADF,RISC,white OLEDs,organic light-emitting diode,reverse intersystem crossing
更新于2025-09-19 17:13:59
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Highly efficient near-UV-excitable Ca2YHf2Al3O12:Ce3+,Tb3+ green-emitting garnet phosphors with potential application in high color rendering warm-white LEDs
摘要： Inorganic phosphors with broadband near-ultraviolet (near-UV) excitation and efficient visible emissions are highly important for fabricating high-performance near-UV-pumped white light-emitting diodes (LEDs). Herein, we reported on novel efficient near-UV-excitable Ce3+/Tb3+ ions co-activated Ca2YHf2Al3O12 (CYHA) green-emitting garnet phosphors, which were successfully prepared through a high-temperature solid-state reaction process. X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, photoluminescence, CIE color coordinates, internal and external quantum efficiency, and temperature-dependent emission spectra were used to characterize the samples. Interestingly, due to the efficient energy transfer from Ce3+ to Tb3+ ions in CYHA, the CYHA:Ce3+,Tb3+ samples presented a wide excitation band in the 370-470 nm region peaking around 408 nm owing to the 4f-5d transition of Ce3+ ions, and under 408 nm excitation they showed intense characteristic sharp green emissions around 543 nm corresponding to the 5D4→7F0-6 transitions of Tb3+ ions. The energy transfer mechanism from Ce3+ to Tb3+ ions was ascribed to the quadruple-quadruple interaction, and the energy transfer efficiency reached as high as 93.2%. Notably, the composition-optimized CYHA:0.03Ce3+,0.6Tb3+ sample exhibited high internal quantum efficiency (IQE) of 78.5% and external quantum efficiency (EQE) of 56%, which were much higher than those of the Tb3+ singly-activated CYHA:0.6Tb3+ sample (IQE = 8%, EQE = 2.2%). Finally, a prototype white LED device was made by combining a 400 nm near-UV-emitting LED chip with the phosphor blend of the as-prepared CYHA:0.03Ce3+,0.6Tb3+ green phosphors, commercial BaMgAl10O17:Eu2+ blue phosphors and commercial CaAlSiN3:Eu2+ red phosphors, which emitted bright warm-white light with good CIE chromaticity coordinates of (0.391, 0.356), low correlated color temperature of 3528 K and high color rendering index of 92.3 under 120 mA driven current. This work opens up new opportunities for the development of efficient color converters toward near-UV-pumped warm-white LEDs with high color rendering index.
关键词： white LEDs,green-emitting garnet phosphors,Ce3+/Tb3+ co-activated,near-UV-excitable,energy transfer
更新于2025-09-19 17:13:59