- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Pyrene[4,5-d]imidazole-based Derivatives with Hybridized Local and Charge Transfer State for Highly Efficient Blue and White Organic Light-emitting Diodes with Low Efficiency Roll-off
摘要： A family of pyrene[4,5-d]imidazole derivatives, PyPA, PyPPA, PyPPAC and PyPAC, with different excited state are successfully developed. Among them, PyPPA and PyPPAC possess hybridized local and charge transfer (HLCT) state endowing them with pure blue fluorescence as well as high quantum yields. The nondoped organic light-emitting diode (OLED) based on PyPPA displays Commission Internationale de L’Eclairage coordinates of (0.14, 0.13) and achieves a maximum external quantum efficiency (EQE) of 8.47%, which are among the highest value reported to date for nondoped blue HLCT OLEDs. The nondoped OLED based on PyPPAC exhibits a maximum luminance of 50046 cd m-2 locating in blue region with CIE coordinates of (0.15, 0.21) and harvests the EQE of 6.74% even when the luminance reached over 10000 cd m?2. In addition, they both reveal ultimate exciton utilizing efficiencies of nearly 100%. The potential of blue emitter of PyPPA with HLCT character for application in white OLED (WOLED) is further tested. The efficient two-color hybrid warm WOLED is successfully achieved, which provides the total EQE, power efficiency and current efficiency of up to 21.19%, 61.46 lm W?1 and 62.13 cd A?1, respectively. The nondoped blue OLEDs and hybrid WOLEDs present good color stabilities with low efficiency roll-offs. Our results prove that taking advantage of the HLCT state, nondoped blue OLEDs as well as hybrid WOLEDs with high performance could be realized, which have a promising prospect for the displays and lightings in the future.
关键词： white OLED,blue luminophore,nondoped blue OLED,HLCT state,pyrene-imidazole
更新于2025-09-23 15:19:57
-
Highly efficient non-doped blue fluorescent OLEDs with low efficiency roll-off based on hybridized local and charge transfer excited state emitters
摘要： Designing a donor-acceptor (D-A) molecule with a hybridized local and charge transfer (HLCT) excited state is a very effective strategy for producing an organic light-emitting diode (OLED) with a high exciton utilization efficiency and external quantum efficiency. Herein, a novel twisting D-π-A fluorescent molecule (triphenylamine-anthracene-phenanthroimidazole; TPAAnPI) is designed and synthesized. The excited state properties of the TPAAnPI investigated through photophysical experiments and density functional theory (DFT) analysis reveal that its fluorescence is due to the HLCT excited state. The optimized non-doped blue OLED using TPAAnPI as light-emitting layer exhibits a novel blue emission with an electroluminescence (EL) peak at 470 nm, corresponding to the Commission International de L’Eclairage (CIE) coordinates of (0.15, 0.22). A fabricated device termed Device II exhibits a maximum current efficiency of 18.09 cd A ?1, power efficiency of 12.35 lm W?1, luminescence of ≈29900 cd cm?2, and external quantum efficiency (EQE) of 11.47%, corresponding to a high exciton utilization efficiency of 91%. Its EQE remains as high as 9.70% at a luminescence of 1000 cd m?2 with low efficiency roll-off of 15%. These results are among the best for HLCT blue-emitting materials involved in non-doped blue fluorescent OLEDs. The performance of Device II highlights a great industrial application potential for the TPAAnPI molecule.
关键词： HLCT,efficiency roll-off,blue emission,non-doped,OLED
更新于2025-09-23 15:19:57
-
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
-
Highly efficient deep-red/near-infrared D-A chromophores based on naphthothiadiazole for OLEDs applications
摘要： Donor-acceptor (D-A) chromophores are an important class of deep-red/near-infrared (DR/NIR) materials. However, efficient D-A DR/NIR fluorescent emitters are rare due to the intrinsic charge-transfer excited-state. In this paper, two novel D-A-type DR/NIR fluorescent emitters with triphenylamine (TPA, donor), naphthothiadiazole (NZ, acceptor), pyrimidine (2TPA-NZN) and benzene (2TPA-BZN) as the π-bridge, are designed and synthesized. The photophysical study and theoretical analysis revealed that the emissive-state of the two materials has hybridized local and charge-transfer (HLCT) characters. This characteristic caused high photoluminescent quantum yield (PLQY) both in solution and doped film. The 2TPA-BZN with a more rigid molecular structure exhibits a lower non-radiative rate constant (knr), resulting in relatively higher PLQY as compared with the 2TPA-NZN. The doped organic light-emitting diodes (OLEDs) devices based on these materials demonstrated excellent maximum external quantum efficiency (EQEmax > 5.0 %) and the emission peak around 665 nm.
关键词： DR/NIR materials,OLEDs,HLCT,Naphthothiadiazole,D-A Chromophores
更新于2025-09-19 17:13:59