High efficiency non-doped deep-blue and fluorescent/phosphorescent white organic light-emitting diodes based on an anthracene derivative

Huang, Yun; Du, Xiaoyang; Tao, Silu; Yang, Xiaoxia; Zheng, Caijun; Zhang, Shun; Lee, Chun‐Sing

doi:10.1016/j.synthmet.2014.10.019

Cited by 33 publications

(10 citation statements)

References 20 publications

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“…The four compounds show similar UV-visible spectra with two absorption bands at 300–350 nm. The former one is attributed to n-π* transition of carbazole [ 16 , 17 ], while the latter one is attributed to the π-π* transition between the imidazole and the substituted benzene ring [ 9 ]. Compared to BCzB-PPI and MoCzB-PPI, the absorption peak around 330 nm of BCzB-PIM and MoCzB-PIM shows a significant blue shift, which is ascribed to the reduced conjugate range of BCzB-PIM and MoCzB-PIM caused by breaking one C–C bond of the phenanthrenere moiety.…”

Section: Resultsmentioning

confidence: 99%

Non-Doped Deep-Blue OLEDs Based on Carbazole-π-Imidazole Derivatives

Xiao

2021

Materials

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In this work, we designed and synthesized four bipolar blue-emitting materials with carbazole, imidazole, and biphenyl as donor, acceptor, and p bridge, respectively. The twisted phenylimidazole acceptor leads to a wider band-gap and hence deeper blue emission than the conjugated phenanthrimidazole acceptor. For the substituents on the carbazole donor, the t-butyl group could prevent the intramolecular charge transfer (ICT) process more effectively than the methoxy group. A non-doped deep-blue organic light-emitting diodes (OLED) is obtained with CIE coordinates of (0.159, 0.080), a maximum luminance of 11,364 cd/m2, and a maximum EQE of 4.43%.

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Section: Resultsmentioning

confidence: 99%

Non-Doped Deep-Blue OLEDs Based on Carbazole-π-Imidazole Derivatives

Xiao

2021

Materials

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“…Anthracene, despite a flat and rigid backbone, has low fluorescence quantum yield in solutions (Φ F = 0.3) due efficient intersystem crossing (ISC) involving higher energy triplet states. , The rate of ISC can be easily tuned by the modification of the molecular backbone at the C-9 and C-10 positions, which results in the rearrangement of energy levels such that S 1 is pushed below T 2 , resulting in the decrease of the ISC rate and Φ F enhancement up to unity . Unfortunately, small 9,10-aryl substituents usually cannot prevent crystallization in thin films; thus, more bulky nonsymmetric fragments, reducing intermolecular interactions, must be used. , However, sometimes it is observed that the introduction of bulkier fragments tends to decrease the fluorescence efficiency, − though no profound analysis of processes behind and their relation to the triplet diffusion and TTA processes and the resulting delayed fluorescence (DF) efficiency has been made.…”

Section: Introductionmentioning

confidence: 99%

Triplet–Triplet Annihilation in 9,10-Diphenylanthracene Derivatives: The Role of Intersystem Crossing and Exciton Diffusion

et al. 2017

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Triplet–triplet annihilation (TTA) is an attractive way to boost the efficiency of conventional fluorescent organic light-emitting diodes (OLEDs). TTA-active anthracene derivatives are often considered as state-of-the-art emitters due to the proper energy level alignment. In this work, TTA properties of a series of highly fluorescent nonsymmetrical anthracene compounds bearing 9-(4-arylphenyl) moiety and 10-(4-hexylphenyl) fragments were assessed. Two different methods to enhance the TTA efficiency are demonstrated. First, the intensity of TTA-based delayed fluorescence directly depended on the intersystem crossing (ISC) rate. This ISC rate can be significantly enhanced in more conjugated compounds due to the resonant alignment of S1 and T2 energy levels. While enhanced ISC rate slightly quenches the intensity of prompt fluorescence, the rise of the triplet population boosts the intensity of resultant delayed fluorescence. Second, the triplet annihilation rate can be significantly enhanced by optimization of triplet exciton diffusion regime in the films of anthracene derivatives. We show that the proper layer preparation technology has a crucial influence on uniformity and energetic disorder of the film. This enhances the nondispersive triplet diffusion and increases the resulting delayed fluorescence intensity.

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“…For instance, devices based on G3MP (A3 and B3) [ 21 ] have a maximum EQE of 12.8% and 10.3%, respectively, both with their EML as host/guest type. M2 [ 49 ] and B [ 50 ] devices with only the carbazole derivative as emitter (like our devices) have a maximum EQE 3.0% and 3.6% respectively (with EL emission around the deep blue). OLEDs with better performance have maximum EQE of 20.1% and 14.4% for DCZ-TTR [ 34 ] and CZ-TTR [ 34 ] respectively, using as EML a host/guest type; they showed similar EL emission, however, such devices have low operation voltage and low current densities values.…”

Section: Resultsmentioning

confidence: 91%

“…When comparing the reached results for our OLEDs devices based on CZ-2 and CZ-1 as EML with those reported in the literature, it can be observed that these measured current efficiencies of 19.3 cd/A and 20.2 cd/A, respectively, are in general similar (or even larger) than those for other OLEDs using also compounds derived from carbazole as emitter material, see Table 2 . For instance: M2 [ 49 ], B [ 50 ] and CP3 [ 32 ] (by spin coating as well as by evaporation), have current efficiencies of 1.53 cd/A (at 4543 cd/m 2 ), 1.8 cd/A (and maximum luminance up to 2267 cd/m 2 ) and 2.53 cd/A (with maximum luminance up to 8235 cd/m 2 ), respectively. This trend was because these OLEDs had larger current densities compared to those for our devices.…”

Section: Resultsmentioning

confidence: 99%

Efficient OLEDs Fabricated by Solution Process Based on Carbazole and Thienopyrrolediones Derivatives

et al. 2018

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Four low molecular weight compounds—three of them new, two of them with carbazole (Cz) as functional group and the other two with thienopyrroledione (TPD) group—were used as emitting materials in organic light emitting diodes (OLEDs). Devices were fabricated with the configuration ITO/PEDOT:PSS/emitting material/LiF/Al. The hole injector layer (HIL) and the emitting sheet were deposited by spin coating; LiF and Al were thermally evaporated. OLEDs based on carbazole derivatives show luminances up to 4130 cd/m2, large current efficiencies about 20 cd/A and, cautiously, a very impressive External Quantum Efficiency (EQE) up to 9.5%, with electroluminescence peaks located around 490 nm (greenish blue region). Whereas, devices manufactured with TPD derivatives, present luminance up to 1729 cd/m2, current efficiencies about 4.5 cd/A and EQE of 1.5%. These results are very competitive regarding previous reported materials/devices.

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High efficiency non-doped deep-blue and fluorescent/phosphorescent white organic light-emitting diodes based on an anthracene derivative

Cited by 33 publications

References 20 publications

Non-Doped Deep-Blue OLEDs Based on Carbazole-π-Imidazole Derivatives

Non-Doped Deep-Blue OLEDs Based on Carbazole-π-Imidazole Derivatives

Triplet–Triplet Annihilation in 9,10-Diphenylanthracene Derivatives: The Role of Intersystem Crossing and Exciton Diffusion

Efficient OLEDs Fabricated by Solution Process Based on Carbazole and Thienopyrrolediones Derivatives

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