- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Novel 9,9-dimethylfluorene-bridged D–π–A-type fluorophores with a hybridized local and charge-transfer excited state for deep-blue electroluminescence with CIE <sub/>y</sub> ～ 0.05
摘要： Deep-blue light emitting materials are of great significance in the fields of commercial full-color organic light-emitting diodes (OLEDs) and solid-state lighting. The hybridized local and charge-transfer excited state (HLCT) is a promising strategy to achieve deep-blue emission and high photoluminescence quantum yield. Based on HLCT, we designed and synthesized two novel donor–π–acceptor, 9,9-dimethylfluorene-bridged fluorophores (DFPBI & TFPBI) for efficient deep-blue OLED applications. Non-doped devices, with DFPBI and TFPBI as emitters, exhibit deep-blue emission with CIE coordinates of (0.154,0.042) and (0.152,0.054), accompanied by good EL performance with maximum external quantum efficiencies (EQEs) of 4.18% and 5.74%, respectively. In particular, the TFPBI-based non-doped device displays a slow efficiency roll-off at high luminance with an EQE of 5.50% and 4.80% at 100 cd m?2 and 1000 cd m?2, respectively. This work not only demonstrates the potential of these two fluorophores in deep-blue OLEDs, but also provides tactics for the design of deep-blue light emitting materials by using the 9,9-dimethylfluorene-bridged D–π–A architecture.
关键词： 9-dimethylfluorene,9,fluorophores,deep-blue emission,HLCT,OLEDs
更新于2025-09-19 17:15:36
-
Achievement of Higha??Performance Nondoped Blue OLEDs Based on AIEgens via Construction of Effective Higha??Lying Chargea??Transfer State
摘要： There remains an urgent demand for high-quality blue luminogens that can simultaneously achieve high photoluminescence quantum yield (PLQY) in film and high exciton utilization efficiency (EUE) in the electroluminescence (EL) process. In this study, a referable molecular design strategy is developed for blue luminogens via constructing low-lying locally excited (LE) state with an aggregation-induced emission (AIE) characteristic and high-lying charge-transfer (CT) state for the effective triplet-to-singlet conversion channel. 2TriPE-BPI-MCN with the insertion of p-cyano and o-methyl groups is designed to compare with its matrix framework (2TriPE-BPI). They have analogous properties of the lowest singlet (S1) states with blue emission and free of concentration quenching in film; however, 2TriPE-BPI-MCN exhibits unusual response for hydrostatic pressure owing to its S2 state CT characteristics. Therefore, 2TriPE-BPI-MCN can harness more electrogenerated excitons than 2TriPE-BPI, resulting in a better EL performance in nondoped blue organic light-emitting diodes (OLEDs) (CIEx,y = 0.153, 0.147) with high external quantum efficiency of 4.6% and negligible efficiency roll-off. These findings could open a feasible avenue to develop high-quality blue luminogens for high-performance nondoped blue OLEDs.
关键词： organic light-emitting diodes,blue emission,hydrostatic pressure,aggregation-induced emission,charge-transfer state
更新于2025-09-19 17:13:59
-
Asymmetric anthracene derivatives as multifunctional electronic materials for constructing simplified and efficient non-doped homogeneous deep blue fluorescent OLEDs
摘要： Herein, large π-conjugated core anthracene with an innate bipolar property was employed to construct multifunctional organic electronic materials. Delicate manipulating molecules via combining anthracene core and large periphery groups, two asymmetric anthracene derivatives namely (4-(10-(4-(9H-1,5-diazacarbazole-9-yl)phenyl)anthracen-9-yl)phenyl)diphenylphosphine oxide (p-PO15NCzDPA) and (3-(10-(3-(9H-1,5-diazarcarbazole-9-yl)phenyl)anthracen-9-yl)phenyl)diphenylphosphine oxide (m-PO15NCzDPA) were firstly designed and developed. The large periphery groups 1,5-diazarcarbazole (15NCz) and diphenylphosphine oxide (PO) efficiently interrupt the intramolecular π-conjugation, presenting an asymmetric bulky periphery enveloping strategy achieving highly twisted structures, which help to realize deep-blue emission. Meanwhile, due to the high PLQY and well-balanced bipolar transport characteristics, desired device addressing the contradiction of efficiency, color gamut and structure complexity is within reach. Detailed device engineering study was carried out, in which p-PO15NCzDPA and m-PO15NCzDPA were functioned as multifunction layers. As expected, p-PO15NCzDPA-based homogenous and unilateral homogenous OLEDs exhibited outstanding performance with impressive EQEmax of 4.55% and 6.40%, deep blue CIE coordinates of (0.152, 0.075) and (0.151, 0.066) at the voltage of 6 V, narrow FWHM of 46 nm and 50 nm, respectively. More importantly, the simplified homogenous device achieved extremely low efficiency roll-offs of 1.3% and 4.8% at 1000 and 5000 cd m-2, respectively. These results are among the most outstanding performance, which provided a guide for further improving the performance of deep blue fluorescent OLEDs and simplifying the structure of OLEDs.
关键词： asymmetric anthracene derivatives,homogenous device structure,multifunctional materials,deep-blue emission,fluorescent OLEDs
更新于2025-09-19 17:13:59
-
Spectrally Tunable and Stable Electroluminescence Enabled by Rubidium Doping of CsPbBr <sub/>3</sub> Nanocrystals
摘要： Perovskite nanocrystals exhibit high photoluminescence quantum yields (PLQYs) and tunable bandgaps from ultraviolet to infrared. However, blue perovskite light-emitting diodes (LEDs) suffer from color instability under applied bias. Developing narrow-bandwidth deep-blue emitters will maximize the color gamut of display technologies. Mixed anion approaches suffer from halide segregation that leads to their spectral instability. Here instead, a mixed cation strategy is employed whereby Rb+ is directly incorporated during synthesis into CsPbBr3 nanocrystals. Blue-emitting perovskite quantum dots (QDs) with stable photoluminescence, PLQYs greater than 60%, tunable emission from 460 to 500 nm, and narrow emission linewidths (<25 nm) are reported. The strategy retains a pure bromine crystal structure resulting in color-pure stable electroluminescence at operating voltages of up to 10 V, peak external quantum efficiencies (EQEs) of 0.87% and 0.11% for sky-blue (490 nm), and deep-blue (464 nm) devices. The sky-blue devices exhibit the highest combined luminance of 93 cd m?2 at an EQE of 0.75%, the best reported to date of perovskite QD LEDs.
关键词： perovskite quantum dots,LEDs,light-emitting diodes,halide perovskites,blue emission
更新于2025-09-19 17:13:59
-
Chlorine Vacancy Passivation in Mixed Halide Perovskite Quantum Dots by Organic Pseudohalides Enables Efficient Rec. 2020 Blue Light-Emitting Diodes
摘要： Blue-emitting perovskites are easily attainable by precisely tuning the halide ratio of mixed halide (Br/Cl) perovskites (MHPs). However, the adjustable halide ratio also hinders the passivation of Cl vacancies – the main source of trap states leading to inferior performance blue MHP light-emitting diodes (LEDs). Here, we report a strategy to passivate Cl vacancies in MHP quantum dots (QDs) using non-polar-solvent-soluble organic pseudohalide (n-dodecylammonium thiocyanate (DAT)), enabling blue MHP LEDs with greatly enhanced efficiency. Density-functional-theory calculations reveal that the thiocyanate (SCN-) groups fill in the Cl vacancies and remove electron traps within the bandgap. DAT-treated CsPb(BrxCl1-x)3 QDs exhibit near unity (~100%) photoluminescence quantum yields; and their blue (~470 nm) LEDs are spectrally stable with an external quantum efficiency (EQE) of 6.3% – a record for perovskite LEDs emitting in the 460-480 nm range relevant to Rec. 2020 display standards – and a half-lifetime of ~99 s.
关键词： light-emitting diodes,organic pseudohalides,blue emission,perovskite,chlorine vacancy passivation,quantum dots
更新于2025-09-19 17:13:59
-
Naphthyridine-based thermally activated delayed fluorescence emitters for highly efficient blue OLEDs
摘要： Two TADF emitters 2,7-di(9H-carbazole)-1,8-naphthyridine (Cz-ND) and 2,7-di(3,6-di-tert-butyl-9H-carbazole)-1,8-naphthyridine (tBuCz-ND) were designed and synthesized. Both of the emitters showed high thermal stabilities and strong blue emissions with high photoluminescence quantum yields, and also exhibited excellent TADF properties with small ?EST values. Consequently, blue organic light-emitting diodes (OLEDs) based on Cz-ND and tBuCz-ND were fabricated, which could achieve maximum external quantum efficiencies (EQEmax) of 15.3 and 20.9%, respectively. Moreover, the devices also exhibited relatively narrow band gaps at 79 and 75 nm with the CIE coordinates of (0.15, 0.17) and (0.15, 0.22), respectively.
关键词： OLED,blue emission,carbazole,thermally activated delayed fluorescence,naphthyridine
更新于2025-09-16 10:30:52
-
Asymmetrically twisted phenanthrimidazole derivatives as host materials for blue fluorescent, green and red phosphorescent OLEDs
摘要： The electroluminescent properties of asymmetrically twisted phenanthrimidazole derivatives comprised of fluorescent anthracene or pyrene unit namely, 1-(1-(anthracen-10-yl)naphthalen-4-yl)-2-styryl-1H-phenanthro[9,10-d]imidazole (ANSPI), 1-(1-(pyren-1-yl) naphthalene-4-yl)-2-styryl-1H-phenanthro[9,10-d]imidazole (PNSPI), 4-(2-(4-(anthracen-9-yl) styryl)-1H-phenanthro[9,10-d]imidazol-1-yl)naphthalene-1-carbonitrile (ASPINC) and 4-(2-(4-(pyren-1-yl)styryl)-1H-phenanthro[9,10-d] imidazol-1-yl)naphthalene-1-carbonitrile (PSPINC) for blue OLEDs have been analyzed. The asymmetrically twisted conformation interrupt π-conjugation effectively results in deep-blue emission. The pyrene containing PSPINC based non-doped blue device (476 nm) shows maximium efficiencies (current efficiency (ηc)-4.23 cd/A; power efficiency (ηp)-2.86 lm/W; external quantum efficiency (ηex)-3.48%: CIE (0.16, 0.17) at 3.10 V. Among the doped blue devices, An(PPI)2:ASPINC shows high efficiencies (ηc-12.13 cd/A; ηp-5.98 lm/W; ηex-6.79%; L-23986 cd m?2; EL-458 nm) at 3.15 V with CIE (0.15, 0.17) than An(PPI)2:PSPINC based device which is inconsistent with non-doped device performances. The green and red PhOLEDs show higher efficiencies with Ir(ppy)3: ASPINC (ηc-50.6 cd/A; ηp-53.4 lm/W; ηex-17.0%; L-61581 cd m?2; EL-501 nm, CIE (0.31, 0.60) at 3.32 V and (bt)2Ir(dipba): ASPINC (ηc-15.2 cd/A; ηp-16.5 lm/W; ηex-14.5%; L-13456 cd m?2; EL-610 nm), CIE (0.63, 0.36) at 3.20 V, respectively. The complete energy transfer between the host and dopant molecules improved the efficiency of PHOLEDs.
关键词： asymmetrically twisted phenanthrimidazole derivatives,electroluminescent properties,energy transfer,blue OLEDs,deep-blue emission
更新于2025-09-11 14:15:04
-
An effective thermally activated delayed fluorescence host material for highly efficient blue phosphorescent organic light-emitting diodes with low doping concentration
摘要： A thermally activated delayed fluorescence (TADF) material BCz-2SO has been designed and synthesized as host for blue phosphorescent organic light-emitting diodes (OLEDs). Photophysical studies and theoretical calculations show that the molecule has a small singlet-triplet energy gap (ΔEST) of 0.345 eV, which is beneficial to the reverse energy transferring between the singlet and triplet state. Thanks to the TADF property, the triplet energy can be transmitted to the singlet state through reverse intersystem crossing (RISC), and then transmitted to the guest through the Fo?rster energy transfer (FET) to achieve 100% utilization of energy. Thus, the triplet–triplet annihilation (TTA) of the blue phosphor can be avoided by the extremely low doping concentration of 1%. By using BCz-2SO as the host of FIrpic, the solution-processed blue phosphorescent device achieves the maximum current efficiency (CE), power efficiency (PE), external quantum efficiency (EQE) and highest brightness of 16.38 cd A-1, 9.04 lm W-1, 7.8% and 16537 cd m-2, respectively. It demonstrates that one can employ the solution-processed method to prepare the high performance phosphorescent OLEDs using the TADF host material we have developed.
关键词： TADF,blue emission,organic light-emitting diodes,low doping concentration,solution-process
更新于2025-09-11 14:15:04
-
Synthesis and Properties of New Imidazole Derivatives Including Various Chromophore for OLEDs
摘要： Two new blue compounds were successfully synthesized by introducing phenanthroimidazole group as a side group into pyrene, a chromophore with good luminous efficiency: 1-(4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-2-(pyren-1-yl)-1H-phenanthro[9,10-d]imidazole (NA-PPI) and 1-(4’-(9H-carbazol-9-yl)-[1,1’-biphenyl]-4-yl)-2-(pyren-1-yl)-1H-phenanthro[9,10-d]imidazole (CP-PPI). The optical and electroluminescence properties of newly synthesized materials were measured. Both materials emit blue or sky-blue photoluminescence in the film state and have a high PLQY value of over 80% in solution state. The synthesized materials were applied as EML in non-doped devices, and high efficiency of 3.51 cd/A and EQE of 2.39% in CP-PPI device were achieved.
关键词： pyrene,blue emission,Organic light-emitting diode,imidazole,fluorescence
更新于2025-09-11 14:15:04
-
Efficient Deep-Blue Electrofluorescence with an External Quantum Efficiency Beyond 10%
摘要： The design of blue fluorescent materials combining both deep-blue emission (CIEy<0.06) and high-efficiency climbing over the typically limited exciton production efficiency of 25% is a challenge for organic light-emitting diodes (OLEDs). In this work, we have synthesized two blue luminogens, trans-9,10-bis(2-butoxyphenyl)anthracene (BBPA) and trans-9,10-bis (2,4-dimethoxyphenyl)anthracene with high photoluminescence quantum yields (PLQYs) of 89.5% and 87.0%, respectively. Intriguingly, we have proposed a strategy to avoid aggregation-caused quenching, which can effectively reduce the undesirable excimeric emission by introducing two host matrices with twisted molecular structure, 9,10-di(naphth-2-yl) anthracene and 10,100-bis-(4-fluorophenyl)-3,30-dimethyl-9,90-bianthracene (MBAn-(4)-F), in the BBPA emission layer. The device containing the EML of BBPA-doped MBAn-(4)-F exhibited a high external quantum efficiency of 10.27% for deep-blue emission with the Commission International de L’Eclairage CIE coordinates of (0.15, 0.05) via the steric effect. Importantly, this represents an advance in deep-blue-emitting fluorescent OLED architectures and materials that meet the requirements of high-definition display.
关键词： external quantum efficiency,deep-blue emission,fluorescent materials,OLEDs,steric effect
更新于2025-09-10 09:29:36