- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Efficient Aggregation-Induced Delayed Fluorescence Luminogens for Solution-Processed OLEDs With Small Efficiency Roll-Off
摘要： Purely organic small molecules with thermally-activated delayed fluorescence have a high potential for application in organic light-emitting diodes (OLEDs), but overcoming severe efficiency roll-off at high voltages still remains challenging. In this work, we design and synthesize two new emitters consisting of electron-withdrawing benzoyl and electron-donating phenoxazine and 9,9-dihexylfluorene. Their electronic structures, thermal stability, electrochemical behaviors, photoluminescence property, and electroluminescence performance are thoroughly investigated. These new emitters show weak fluorescence in dilute solution, but they can emit strongly with prominent delayed fluorescence in the aggregated state, indicating the aggregation-induced delayed fluorescence (AIDF) character. The solution-processed OLEDs based on the two emitters show high external quantum efficiency of 14.69%, and the vacuum-deposited OLEDs can also provide comparable external quantum efficiency of 14.86%. Significantly, roll-offs of the external quantum efficiencies are very small (down to 0.2% at 1,000 cd m?2) for these devices, demonstrating the evidently advanced efficiency stability. These results prove that the purely organic emitters with AIDF properties can be promising to fabricate high-performance solution-processed OLEDs.
关键词： thermally activated delayed fluorescence,aggregation-induced fluorescence,efficiency roll-off,delayed fluorescence,organic light-emitting diodes,electroluminescence
更新于2025-09-23 15:19:57
-
Membrane modification with semiconductor diode laser to reduce membrane biofouling for external MBR system and modelling study
摘要： Membrane biofouling is one of the major problem for membrane-based wastewater treatment. In this study, we used laser technology to modify ultrafiltration polyethersulfone (UP150) membrane in order to decrease membrane biofouling. Semiconductor laser diodes with different wavelengths of 405, 520, and 658 nm and different power density of 1.5, 2.0, 2.5 mW were used to improve membrane structure against biofouling. The pure water permeability (Lp), contact angle, porosity, and the average pore size were determined for pristine and modified membranes. Lp value of the pristine UP150 membrane (1102.0 L/(m2.h.bar)) was higher than modified membrane (19.2 L/(m2.h.bar)). The contact angle values were presented that hydrophilicity was decreased from 75.1° to 61.2° for 2 h at 2.5 mW laser irradiation. Membrane porosity increased from 63.2 to 67.7%; however, the average pore size decreased from 88 to 23 nm after laser modification. The impact of laser wavelength and irradiation time on the rejection of protein (bovine serum albumin, BSA) and the fractions of soluble microbial products (as protein and carbohydrate) was systematically investigated. A maximum rejection of 32.2% and 41.9% was obtained for carbohydrate and protein when activated sludge was filtrated through modified membrane. Moreover, 100% BSA rejection was obtained by the modified membrane when BSA solution was filtrated. The modified membranes were extensively characterized by AFM, FTIR, SEM, and mechanical strength test analyses to observe morphological changes of the membrane before and after modification. The results showed that laser irradiation was changed the membrane morphology. Our results presented that laser-modified membranes with red wavelength changed the pore size, porosity, hydrophilicity of the pristine membrane. Also, membrane surface melting was revealed with a study called “Thermal Analysis on Membrane Surface Modelled 3D” using Solidworks CAD/CAM software. The results obtained from Solidworks thermal analysis was presented with 98.7% ratio of successful approach.
关键词： membrane biofouling,Membrane modification,semiconductor diode laser,activated sludge filtration
更新于2025-09-23 15:19:57
-
Organic and quantum-dot hybrid white LEDs using a narrow bandwidth blue TADF emitter
摘要： White electroluminescence is of particular importance for high resolution full-color flexible displays which employ the down-conversion scheme to generate the individual red, green and blue emissions from the color filters. Quantum dots (QD) light emitting diodes possess ultrahigh brightness and considerably narrow full-width-half-maximum (FWHM) spectra. Nevertheless, inefficient blue QDs limit the overall device performances. Herein, we introduced a boron-based blue thermally activated delayed fluorescence compound and utilized the host-guest system to construct the solution-process white devices. Red and green QDs combined with the blue emitter make it feasible to design the flexible white devices with the sharp peaks and thus intrinsically wide color gamuts. The proof-of-concept hybrid white devices with a single emissive layer exhibited the external quantum efficiencies of 6.9% (on rigid substrate) and 2.3% (on flexible substrate). The color mixing effect and energy transfer among the lumophores were exemplified with three sharp peaks at around 464, 538 and 622 nm, respectively accompanied with the corresponding FWHM of 30, 34 and 31 nm of each component.
关键词： Thermally activated delayed fluorescence,Color gamuts,White electroluminescence,Flexible displays,Quantum dots
更新于2025-09-23 15:19:57
-
Diboron-Based Delayed Fluorescent Emitters with Orange-to-Red Emission and Superior Organic Light-Emitting Diode Efficiency
摘要： For the application of OLEDs in lighting and panels, the basic requirement is to include a full spectrum color range. Compared with the development of blue and green luminophores in thermally activated delayed fluorescence (TADF) technology, the progress of orange-to-red materials is slow and needs further investigation. In this study, three diboron compound-based materials, dPhADBA, dmAcDBA, and SpAcDBA, were designed and synthesized by nucleophilic arylation of three amine donors on 9,10-diboraanthracene (DBA) in a two-step reaction. With increasing electron-donating ability, they show orange-to-red emission with TADF characteristics. The electroluminescence (EL) of these diboron compounds exhibits emissions λmax at 613, 583, and 567 nm, for dPhADBA, dmAcDBA, and SpAcDBA, respectively. It is noteworthy that the rod-like D-A-D structures can achieve high horizontal ratios (84~86%) and outstanding device performance for orange-to-red TADF OLEDs: the highest external quantum efficiencies (ηEQE) for dPhADBA, dmAcDBA, and SpAcDBA are 11.1 ± 0.5%, 24.9 ± 0.5%, and 30.0 ± 0.8%, respectively. Therefore, these diboron-based molecules offer a promising avenue for the design of orange-to-red TADF emitters and the development of highly efficient orange-to-red OLEDs.
关键词： thermally activated delayed fluorescence,9,10-diboraanthracene,horizontal dipole ratio,diboron compound,orange-red color,organic light-emitting diode
更新于2025-09-23 15:19:57
-
PACAP through EGFR transactivation preserves human corneal endothelial integrity
摘要： The corneal endothelium is composed of a single hexagonal‐shaped cells layer adherent to the Descemet's membrane. The primary function of these cells is maintaining of tissue clarity by regulating its hydration. Trauma, aging or other pathologies cause their loss, counterbalanced by enlargement of survived cells fluid pumping to and from the stroma. unable to guarantee an efficient Regenerative medicine using human corneal endothelial cells (HCECs) isolated from peripheral corneal‐scleral tissue of a donor could be an attractive solution, overcoming transplantation problems. In a previous study, we have demonstrated that HCECs treatment with pituitary adenylate cyclase–activating polypeptide following growth factors deprivation prevents their degeneration. (PACAP) However, the molecular mechanism mediating this effect has not been clarified, yet. Here, we have shown for the first time the expression of PACAP and its receptor (PAC1R) in human corneal endothelium and demonstrated that this peptide, selectively binding to PAC1R, induces epidermal growth factor receptor (EGFR) phosphorylation and the MAPK/ERK1/2 signaling pathway activation. In conclusion, our data have suggested that PACAP could represent an important trophic factor in maintaining human corneal endothelial integrity through EGFR transactivation. Therefore, PACAP, as well as epidermal growth factor and fibroblast growth factor, could co‐operate to guarantee tissue physiological functioning by supporting corneal endothelial barrier integrity.
关键词： epidermal growth factor receptor,human corneal endothelial cells,mitogen‐activated protein kinase,pituitary adenylate cyclase–activating polypeptide
更新于2025-09-23 15:19:57
-
Dual nature of exciplexes: exciplex-forming properties of carbazole and fluorene hybrid trimers
摘要： Two exciplexes were detected for the first time for the known exciplex-forming system consisting of electron donating 1,3-bis-(N-carbazolyl)benzene and electron accepting 2,4,6-tris[3-(diphenyl-phosphinyl)phenyl]-1,3,5-triazine. Exploiting thermal treatment, sky-blue (high-energy) and orange (low-energy) exciplexes were observed for a solid-state mixture of the compounds under electrical excitation. Similarly, stable high-energy and low-energy exciplexes were observed for new exciplex-forming systems consisting of 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine and one of four selected carbazole and fluorene hybrid trimers as donors. The high-energy exciplexes were observed when there was a small energy barrier between the locally excited state and the high-energy exciplex state. A large energy barrier between the locally excited state and the low-energy exciplex state was the reason that the dual nature of exciplexes was not discovered yet. Emission of both exciplexes was observed in electroluminescence spectra of exciplex-interface based devices using developed exiplex-forming systems as emitters. Observed under optical and electrical excitations, the low-energy exciplexes were separated using thermal treatment of the studied exciplex-forming systems. The exciplex-forming system consisting of 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine and 3,6-di(9-carbazolyl)-9-(2-ethylhexyl)carbazole, which exhibits thermally activated delayed fluorescence, showed the best performance in organic light-emitting diodes (OLEDs) based on interface and volume exciplex emitters. The best device showed maximum external quantum and maximum current efficiencies of 18% and 54 cd A?1 respectively. Additionally, white OLEDs were fabricated exploiting sky-blue and orange emissions from a single exciplex-forming system. Our findings provide evidence of the dual nature of exciplexes and pave the way towards design of new exciplex-forming systems with high photoluminescence quantum yields and efficient exciplex-based devices.
关键词： OLEDs,fluorene,exciplexes,hybrid trimers,thermally activated delayed fluorescence,carbazole
更新于2025-09-19 17:15:36
-
Mn <sup>4+</sup> -activated BaLaMgSbO <sub/>6</sub> double-perovskite phosphor: a novel high-efficiency far-red-emitting luminescent material for indoor plant growth lighting
摘要： In the present work, novel high-efficiency Mn4+-activated BaLaMgSbO6 (BLMS) far-red-emitting phosphors used for plant growth LEDs were successfully synthesized via a solid-state reaction method. X-ray diffraction (XRD), photoluminescence (PL), temperature-dependent PL, CIE color coordinates, and lifetimes as well as internal quantum efficiency (IQE) were used to characterize the phosphor samples. The excitation spectrum of the as-obtained BLMS:Mn4+ phosphors presented two wide bands covering 250–550 nm and the emission spectrum exhibited a far-red emission band in the range of 650–800 nm peaked at 700 nm. Concentration-dependent PL properties of BLMS:Mn4+ phosphors were studied. The optimal doping concentration of Mn4+ ions was 0.6 mol%, and the concentration quenching mechanism was determined to be the nonradiative energy transfer among the nearest-neighbor Mn4+ activators. Impressively, the BLMS:0.6%Mn4+ sample showed an outstanding IQE of 83%. In addition, the luminescence thermal quenching characteristics were also analyzed. Furthermore, the PL spectrum of BLMS:0.6%Mn4+ sample was compared with the absorption spectrum of phytochrome PFR. Finally, after combining BLMS:0.6%Mn4+ phosphors with a 365 nm near-UV LED chip, a far-red light-emitting diode (LED) device was successfully achieved to demonstrate its possible applications in plant growth LEDs.
关键词： far-red-emitting,solid-state reaction,Mn4+-activated,internal quantum efficiency,plant growth LEDs,phosphor,BaLaMgSbO6
更新于2025-09-19 17:15:36
-
Phosphane tuning in heteroleptic [Cu(N^N)(P^P)] <sup>+</sup> complexes for light-emitting electrochemical cells
摘要： The synthesis and characterization of five [Cu(P^P)(N^N)][PF6] complexes in which P^P = 2,7-bis(tert-butyl)-4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (tBu2xantphos) or the chiral 4,5-bis(mesitylphenylphosphino)-9,9-dimethylxanthene (xantphosMes2) and N^N = 2,2’-bipyridine (bpy), 6-methyl-2,2’-bipyridine (6-Mebpy) or 6,6’-dimethyl-2,2’-bipyridine (6,6’-Me2bpy) are reported. Single crystal structures of four of the compounds confirm that the copper(I) centre is in a distorted tetrahedral environment. In [Cu(xantphosMes2)(6-Mebpy)][PF6], the 6-Mebpy unit is disordered over two equally populated orientations and this disorder parallels a combination of two dynamic processes which we propose for [Cu(xantphosMes2)(N^N)]+ cations in solution. Density functional theory (DFT) calculations reveal that the energy difference between the two conformers observed in the solid-state structure of [Cu(xantphosMes2)(6-Mebpy)][PF6] differ in energy by only 0.28 kcal mol?1. Upon excitation into the MLCT region (λexc = 365 nm), the [Cu(P^P)(N^N)][PF6] compounds are yellow to orange emitters. Increasing the number of Me groups in the bpy unit shifts the emission to higher energies, and moves the Cu+/Cu2+ oxidation to higher potentials. Photoluminescence quantum yields (PLQYs) of the compounds are low in solution, but in the solid state PLQYs of up to 59% (for [Cu(tBu2xantphos)(6,6’-Me2bpy)]+) are observed. Increased excited-state lifetimes at low temperature are consistent with the complexes exhibiting thermally activated delayed fluorescence (TADF). This is supported by the small energy difference calculated between the lowest-energy singlet and triplet excited states (0.17–0.25 eV). The compounds were tested in simple bilayer light-emitting electrochemical cells (LECs). The optoelectronic performances of complexes containing xantphosMes2 were generally lower with respect to those with tBu2xantphos, which led to bright and efficient devices. The best performing LECs were obtained for the complex [Cu(tBu2xantphos)(6,6’-Me2bpy)][PF6] due to the increased steric hindrance at the N^N ligand, resulting in higher PLQY.
关键词： photoluminescence quantum yields,heteroleptic copper complexes,light-emitting electrochemical cells,thermally activated delayed fluorescence,Phosphane tuning
更新于2025-09-19 17:15:36
-
Enhanced UV-Vis-NIR activated photocatalytic activity from Fe <sup>3+</sup> -doped BiOBr:Yb <sup>3+</sup> /Er <sup>3+</sup> upconversion nanoplates: synergistic effect and mechanism insight
摘要： Upconversion (UC) materials are recognized as promising candidates to harvest solar energy for photocatalysis. In this work, a simple strategy for simultaneously enhancing the UC luminescence and photocatalytic efficiency of BiOBr:Yb3+/Er3+ nanoplates through Fe3+ ion doping is reported. Compared to the Fe3+-free sample, the UC emission intensity was significantly enhanced through tailoring of the crystal symmetry by Fe3+ ions. Experiment and DFT calculations reveal that the introduction of Fe3+ ions resulted in the formation of an impurity energy level, extending to the light absorption region. As expected, the Fe3+-doped BiOBr:Yb3+/Er3+ nanoplates exhibit a wide photoresponse from the UV to NIR regions, good stability, and obviously enhanced photocatalytic activities compared with the BiOBr:Yb3+/Er3+ nanoplates in the degradation of RhB. The boosted photocatalytic activity can be attributed to the synergic effect of the efficient utilization of UC luminescence and Fe3+ doping, where Fe3+ doping could improve the light harvesting capacity, enhance the separation efficiency of electron and hole (e?/h+) pairs, and promote the production of highly oxidative species. This work not only provides a promising system for the efficient utilization of solar light, but also offers a feasible guideline for the further design of broad-spectrum active photocatalysts.
关键词： Enhanced UV-Vis-NIR activated photocatalytic activity,mechanism insight,Fe3+-doped BiOBr:Yb3+/Er3+ upconversion nanoplates,synergistic effect
更新于2025-09-19 17:15:36
-
Achieving Dual-Emissive and Time-Dependent Evolutive Organic Afterglow by Bridging Molecules with Weak Intermolecular Hydrogen Bonding
摘要： It is discovered that “bridging” traditional persistent room-temperature phosphorescence (pRTP) dibenzofuran moieties by intermolecular hydrogen bonding can induce interesting photophysical properties. The light-emitting material 4-(4-((4-methoxyphenyl)sulfonyl)phenyl)dibenzo[b,d]furan (SOBF-OMe) is synthesized and excitingly shows novel dual-emissive afterglow material properties in which orange pRTP (at ≈580 nm, 627 ms) from the dibenzofuran moiety and another blue ultralong intermolecular charge transfer emission (≈476 nm, 204 ms, with TADF characteristics) can be detected. Due to the different decay lifetimes, the ratio of the two afterglow emission bands continuously changes. Accordingly, the emission colors are unusually tuned gradually from cold-white to orange during the afterglow decay process. The blue afterglow emission, which relates to intermolecular interactions, is sensitive to mechanical stimuli and the afterglow emission properties of SOBF-OMe (single-emissive or dual-emissive) can easily be manipulated by grinding/fuming. This single-component material is a rare example of a light-emitting compound showing dual-emissive and real-time changing afterglow properties in which a rational bridging strategy via weak intermolecular hydrogen bonding is utilized.
关键词： afterglow emission,dual-emissive,thermally activated delayed fluorescence,intermolecular charge transfer,hydrogen bonds
更新于2025-09-19 17:15:36