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Trap-Controlled White Electroluminescence From a Single Red-Emitting Thermally Activated Delayed Fluorescence Polymer
摘要： Single white-emitting polymers have been reported by incorporating the second-generation carbazole dendron into the side chain of a red-emitting thermally activated delayed ?uorescence (TADF) polymer. Due to the prevented hole trap effect, in this case, excitons can be generated simultaneously on the polymeric host and the red TADF dopant to give a dual emission. Consequently, a bright white electroluminescence is achieved even at a dopant loading as high as 5 mol.%, revealing a maximum luminous ef?ciency of 16.1 cd/A (12.0 lm/W, 8.2%) and Commission Internationale de l’Eclairage (CIE) coordinates of (0.42, 0.32). The results clearly indicate that the delicate tuning of charge trap is a promising strategy to develop ef?cient single white-emitting polymers, whose low-band-gap chromophore content can be up to a centesimal level.
关键词： carbazole dendron,thermally activated delayed ?uorescence (TADF),dual emission,charge trap,single white-emitting polymers
更新于2025-09-23 15:21:01
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Red-Emitting Thermally Activated Delayed Fluorescence Polymers with Poly(fluorene- <i>co</i> -3,3′-dimethyl diphenyl ether) as the Backbone
摘要： A series of red-emitting thermally activated delayed ?uorescence (TADF) polymers have been designed and synthesized based on poly(?uorene-co-3,3′-dimethyl diphenyl ether) (PFDMPE) as the backbone. Compared with poly?uorene (PF, 2.16 eV), the introduction of 3,3′-dimethyl diphenyl ether into the main chain of PFDMPE leads to the increased triplet energy of 2.58 eV, which is higher enough than the tethered red TADF guest (2.13 eV) to prevent the unwanted triplet energy back-transfer. Meanwhile, there is a good overlap between the absorption spectrum of the red guest and the photoluminescence (PL) spectrum of the polymeric host, ensuring the e?cient energy transfer from host to guest. Consequently, the resultant polymers PFDMPE-R01 to PFDMPE-R10 in solid states show obvious red TADF properties with delayed ?uorescence lifetimes of 126?191 μs and PL quantum yields of 0.18?0.55. Among them, PFDMPE-R05 obtains the best device performance, revealing a bright red electroluminescence peaked at 606 nm and a promising current e?ciency of 10.3 cd/A (EQE = 5.6%). The results compete well with those of red phosphorescent polymers and indicate that PFDMPE other than PF is a suitable polymeric host for the construction of e?cient red TADF polymers.
关键词： PFDMPE,electroluminescence,polymers,poly?uorene,triplet energy,PF,energy transfer,red-emitting,thermally activated delayed ?uorescence,poly(?uorene-co-3,3′-dimethyl diphenyl ether)
更新于2025-09-23 15:21:01
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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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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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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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Mixed-Host Systems with a Simple Device Structure for Efficient Solution-Processed Organic Light-Emitting Diodes of a Red-Orange TADF Emitter
摘要： Charge balance, concentration quenching, and exciton con?nement are the most important factors for realizing the use of thermally activated delayed ?uorescence (TADF) emitters for organic light-emitting diodes. Red-orange organic light-emitting diodes of a TADF emitter 2-[4 (diphenylamino)phenyl]-10,10-dioxide-9H-thioxanthen-9-one (TXO-TPA) have been reported by doping in a mixed p-type host system of poly(N-vinylcarbazole) (PVK) and 1,3-bis(N-carbazolyl)benzene (mCP) via solution-processed. We have demonstrated the peak external quantum e?ciency of 9.75%, maximum current e?ciency of 19.36 cd/A, and power e?ciency of 12.17 lm/W along with a CIE coordinate of (0.45, 0.51). The devices were compared with di?erent doping concentrations of TXO-TPA, and a comparative investigation on the e?ect of the thickness electron transport layer was studied. The results clearly indicated that this solution-processed TXO-TPA device structure is a promising strategy to develop highly e?cient but simple OLED structures.
关键词： external quantum e?ciency,thermally activated delayed ?uorescence,red-orange,solution-processed,organic light-emitting diodes
更新于2025-09-16 10:30:52
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Through-space charge transfer in luminophore based on phenyl-linked carbazole- and phthalimide moieties utilized in cyan-emitting OLEDs
摘要： Two new carbazole-containing aromatic imides were synthesized by three-step synthetic pathway with the moderate yields up to 76%. The compounds were investigated theoretically. TD-DFT computational studies revealed low singlet-triplet energy di?erences. The compounds were found to have relatively high thermal stability with 5% mass loss temperatures in the range of 280–310 °C. Phthalimide-based compound exhibited aggregation-induced emission enhancement and thermally activated delayed ?uorescence with photo-luminescence quantum e?ciency of 20% in the solid state. Structure-properties relationship of this compound was investigated and it was found that charge-transfer through space mechanism is responsible for the emission. Series of green-emitting doped and non-doped electroluminescent devices were fabricated based on the carbazole-phthalimide derivative were fabricated to reveal best-performing mCP-doped device demonstrating maximum external quantum e?ciency of 2.4% with current e?ciency of 6.6 cd/A and power e?ciency of 4.0 lm/W with maximum brightness of 8300 cd/m2.
关键词： Cyan-emitting OLED,Aromatic imide,Through-space charge transfer,Aggregation-induced emission enhancement,Thermally activated delayed ?uorescence
更新于2025-09-12 10:27:22