Dynamically Adaptive Characteristics of Resonance Variation for Selectively Enhancing Electrical Performance of Organic Semiconductors

Tao, Ye; Xiao, Jianjian; Zheng, Chao; Zhang, Zhen; Yan, Mingkuan; Chen, Runfeng; Zhou, X. H.; Li, Huanhuan; An, Zhongfu; Wang, Zhixiang; Xu, Hui; Huang, Wei

doi:10.1002/anie.201304540

Cited by 80 publications

(66 citation statements)

References 32 publications

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“…As to the photophysical properties ( Figure a,b; and Table S2, Supporting Information), the absorption band of DPhPz is significantly redshifted in comparison to that of triphenylamine ( TPA ) due to the extended aromaticity, when considering that DPhPz is formed by fusing the nearby two phenyls of TPA with a diphenylsilane bridge to enlarge the aromatic plane. Similarly, rDPhPz with the embedded carbazole moiety exhibits characteristic π–π* transition absorption bands of carbazoles, but are also significantly redshifted spectrum after fusing with azasiline . As discussed above, the introduction of bulky phenyl substituents significantly reduces the intermolecular interactions despite their highly rigid single molecular structures.…”

Section: Methodsmentioning

confidence: 89%

“…Such high E T s, which are much higher than the commonly used blue phosphorescent guest of bis[(4,6‐difluorophenyl)‐pyridinato‐N,C2′](picolinate) iridium(III) (FIrpic, E T = 2.65 eV), are very impressive, especially because those E T s were achieved in rigid molecules with highly π‐extended molecular architectures. It is well known that high E T is essential to support efficient energy transfer from hosts to guests and confine triplet excitons on phosphor guests for high‐luminescence efficiencies …”

Section: Methodsmentioning

confidence: 99%

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High‐Performance All‐Aryl Phenazasilines via Metal‐Free Radical‐Mediated CH Silylation for Organic Light‐Emitting Diodes

Shen

Chen

et al. 2018

Advanced Optical Materials

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complicated synthetic routes to prepare heteroatom-containing materials with specifically introduced heteroatoms on the desired positions of an aromatic molecule, and it becomes even more challenging, when multiple and/or multitype heteroatoms are designed to be introduced. [5][6][7] Phenazasilines, which contain both Si and N heteroatoms in a fused six-membered ring, are typical examples. [8,9] Structurally similar to the popular donor moiety of 9,10-dihydroacridine by replacing its 9-C with Si, [10] phenazasilines can benefit from both 9,10-dihydroacridine-alike architecture and Si incorporation, exhibiting intrinsically promising properties as hole-transporting materials for organic field effect transistors [11] with a hole mobility of 10 −4 cm 2 V −1 s −1 and an ON-OFF ratio close to 10 5 , thermally activated delayed fluorescence (TADF) emitters [12] for organic light emitting diodes (OLEDs) with external quantum efficiency (EQE) up to 22.3%, and host materials [13] for phosphorescent OLEDs (PhOLEDs) with EQE of 12%. Nevertheless, the synthesis of phenazasilines, either traditionally through extended heating of diphenylsilane with phenothiazines [14] and cyclization reaction between 2,2′-dilithiodiarylamine intermediates and dichlorosilanes, [15] or recently by rhodium-catalyzed double activation of SiH and CH bonds for dehydrogenation and SiC coupling, [13] suffers from the low yields, complicated precursors, long synthetic routes, or high chemical costs. These synthetic difficulties significantly hinder the investigations and applications of phenazasilines, although they have already shown promising optical and electronic properties for high-performance device applications due to the combined effects of Si and N heteroatom incorporation.With planar π-conjugated molecular structure, phenazasilines are especially attractive for OLEDs to function as emitters, charge transporters, and host materials. However, due to the planar molecular geometry of phenazasilines with a phenyl-fused azasiline ring, strong π-π stacking and heavy intermolecular interaction are generally observed, especially in the solid state, leading to broad and redshifted excimer emission and coarse film morphology. [16,17] To alleviate the intermolecular interactions, bulky phenyl substituents on the Heteroatom-containing organic molecules show a unique combination of properties for high-performance optoelectronic applications. With both Si and N heteroatoms in an aromatic architecture, phenazasilines are promising for optoelectronic devices, except for their synthetic difficulties. Through a newly developed two-step SiH/CH coupling silylation in a metal-free intramolecular radical-mediated catalysis mechanism, all-aryl phenazasilines that can be hardly synthesized by previous methods are facilely prepared and found to have excellent optoelectronic properties with both high thermal stability and high solubility due to the effects of bulky diphenyl substituents on Si, which cannot only strengthen the intramolecular interactions but also ...

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Section: Methodsmentioning

confidence: 89%

Section: Methodsmentioning

confidence: 99%

High‐Performance All‐Aryl Phenazasilines via Metal‐Free Radical‐Mediated CH Silylation for Organic Light‐Emitting Diodes

Shen

Chen

et al. 2018

Advanced Optical Materials

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“…52-53 Recently, we reported a D-A-D host with a structure of two carbazole donors linked by a phenylphosphine oxide acceptor, which endowed its FIrpic-based blue PHOLEDs with favorable performance owing to its unique dynamically adaptive electrical characteristic. 54 Nevertheless, a more in-depth 75 This journal is © The Royal Society of Chemistry [year]90 CDCl 3 , 400 MHz): δ = 8.19-8.22 (d, J = 7.6 Hz, 2H), 7.77-7.79 (d, J = 8.8 Hz, 2H), 7.41-7.51 (m, 6H), 7.35-7.38 ppm (t, J = 6.8 Hz, 2H); LDI-TOF: m/z (%): 321 (100) [M + ]; elemental analysis (%) for C 18 H …”

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confidence: 99%

Ternary donor–acceptor phosphine oxide hosts with peculiar high energy gap for efficient blue electroluminescence

et al. 2015

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Ternary donor (D)-acceptor (A)-acceptor (A) molecules are commonly considered as low triplet (T 1 ) energy systems for specific applications. In this work, this preoccupation was redressed by a triangleshaped D-A-A molecule PCImbPO with peculiarly high triplet energy of 3.0 eV. Profiting from the enhanced D-A electronic coupling, electron injecting and transporting ability of PCImbPO was 10 dramatically improved with negligible influences on its highest occupied molecular orbital (HOMO) characteristic. Its particular T 1 configuration adjustment further gives rise to the separated frontier MO and T 1 locations, beneficial to suppress quenching effects. By utilizing PCImbPO as host in blue phosphorescent organic light-emitting diodes (PHOLEDs) and thermally activated delayed fluorescence devices, the impressively high external quantum efficiency beyond 22 and 12% were achieved, 15 respectively. This work established a new understanding of high-energy-gap complicated D-A systems. 65 III), ternary D-A system is almost ideal as host materials with the independent highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and T 1 locations, which is conducive to suppressing polarization-induced exciton decomposition (PIED) 51 and triplet-polaron quenching (TPQ) 70 effects. 52-53 Recently, we reported a D-A-D host with a structure of two carbazole donors linked by a phenylphosphine oxide acceptor, which endowed its FIrpic-based blue PHOLEDs with favorable performance owing to its unique dynamically adaptive electrical characteristic. 54 Nevertheless, a more in-depth 75 This journal is © The Royal Society of Chemistry [year]90 CDCl 3 , 400 MHz): δ = 8.19-8.22 (d, J = 7.6 Hz, 2H), 7.77-7.79 (d, J = 8.8 Hz, 2H), 7.41-7.51 (m, 6H), 7.35-7.38 ppm (t, J = 6.8 Hz, 2H); LDI-TOF: m/z (%): 321 (100) [M + ]; elemental analysis (%) for C 18 H

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“…The effective modulation of this obstacle by resonance variation and its dynamically adaptive characteristics in the charge-transfer process can be potentially realized in carbazole derivatives. [60] Other heavy heteroatoms except oxygen, sulfur, carbon, and phosphorus that have already been used to substitute the nitrogen and carbon atoms in the skeleton of carbazole are expected to produce more pronounced effects on the general optoelectronic properties of the obtained hosts. [61,62] As for carbazole derivatives obtained by different methods, we cannot determine which one is the best unit for hosts.…”

Section: Discussionmentioning

confidence: 99%

Hosts for High‐Performance Phosphorescent Organic Light‐Emitting Diodes Based on Carbazole Derivatives

Jiang

2014

Asian J Org Chem

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Organic electroluminescent (EL) materials have many advantages when compared with their inorganic counterparts and, therefore, they have a wide range of potential applications in communication, information display, illumination, and so on. Phosphorescent organic lightemitting diodes (PHOLEDs) that contain late transition-metal complexes as emitters are particularly attractive due to their ability to harvest singlet and triplet excitons, which makes it possible to achieve an internal quantum efficiency of 100 %. To suppress concentration quenching, a phosphorescent emitter is usually dispersed in a suitable host to obtain a high photoluminescent quantum yield. Developing a host with a suitable triplet energy level, charge-transporting ability, and thermal and film stability is thus the key to improving the performance of PHOLEDs. Carbazole-based chromophores are widely used in the synthesis of highly efficient hosts for PHOLEDs. However, these compounds are not universal or unique segments for constructing high performance hosts. Herein, up-to-date methods for chemical modifications to obtain hosts for high-performance PHOLEDs based on carbazole derivatives are presented in detail. These methods include heterocycle replacement and extension of the conjugated structure of the carbazole skeleton. Finally, some issues to be addressed and hotspots to be further investigated are also discussed.

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Dynamically Adaptive Characteristics of Resonance Variation for Selectively Enhancing Electrical Performance of Organic Semiconductors

Cited by 80 publications

References 32 publications

High‐Performance All‐Aryl Phenazasilines via Metal‐Free Radical‐Mediated CH Silylation for Organic Light‐Emitting Diodes

High‐Performance All‐Aryl Phenazasilines via Metal‐Free Radical‐Mediated CH Silylation for Organic Light‐Emitting Diodes

Ternary donor–acceptor phosphine oxide hosts with peculiar high energy gap for efficient blue electroluminescence

Hosts for High‐Performance Phosphorescent Organic Light‐Emitting Diodes Based on Carbazole Derivatives

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