- Blue organic light-emitting diodes containing anthracene derivatives with end-capping phenyl group
-
We have synthesized and characterized new blue host materials for OLEDs; 9,10-di-o-tolylanthracene (1), 2-tert-butyl-9,10-diphenylanthracene (2), 10,10-diphenyl-9,9-bianthracene (3), and 1,4-bis(10-phenylanthracen-9-yl)benzene (4). To explore electroluminescent properties of these materials, multilayered OLEDs with the configuration of ITO/NPB (50nm)/Blue emitters (1-4) (30nm)/Liq (2nm)/Al (100nm) were fabricated. Among those non-doped devices, the device 4a employing 4 as an emitter showed high efficiencies of 4.11 cd/A, 3.31 lm/W, and 2.35%, respectively. The device 2b employing 2 as host material for PFVtPh blue dopant material exhibited excellent efficiencies with 5.64 cd/A, 4.14 lm/W, and 4.54%. Taylor and Francis Group, LLC.
- Jang, Heung Soo,Lee, Kum Hee,Lee, Seok Jae,Kim, Young Kwan,Yoon, Seung Soo
-
-
Read Online
- Diphenylanthracene Dimers for Triplet-Triplet Annihilation Photon Upconversion: Mechanistic Insights for Intramolecular Pathways and the Importance of Molecular Geometry
-
Novel approaches to modify the spectral output of the sun have seen a surge in interest recently, with triplet-triplet annihilation driven photon upconversion (TTA-UC) gaining widespread recognition due to its ability to function under low-intensity, noncoherent light. Herein, four diphenylanthracene (DPA) dimers are investigated to explore how the structure of these dimers affects upconversion efficiency. Also, the mechanism responsible for intramolecular upconversion is elucidated. In particular, two models are compared using steady-state and time-resolved simulations of the TTA-UC emission intensities and kinetics. All dimers perform TTA-UC efficiently in the presence of the sensitizer platinum octaethylporphyrin. The meta-coupled dimer 1,3-DPA2 performs best yielding a 21.2% upconversion quantum yield (out of a 50% maximum), which is close to that of the reference monomer DPA (24.0%). Its superior performance compared to the other dimers is primarily ascribed to the longer triplet lifetime of this dimer (4.7 ms), thus reinforcing the importance of this parameter. Comparisons between simulations and experiments reveal that the double-sensitization mechanism is part of the mechanism of intramolecular upconversion and that this additional pathway could be of great significance under specific conditions. The results from this study can thus act as a guide not only in terms of annihilator design but also for the design of future solid-state systems where intramolecular exciton migration is anticipated to play a major role.
- Olesund, Axel,Gray, Victor,M?rtensson, Jerker,Albinsson, Bo
-
p. 5745 - 5754
(2021/05/06)
-
- Absence of delayed fluorescence and triplet-triplet annihilation in organic light emitting diodes with spatially orthogonal bianthracenes
-
Two compounds, 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), which has a single anthracene unit, and 10,10′-diphenyl-9,9'-bianthracene (PPBA), which has two spatially orthogonal anthracene units, were compared and investigated in terms of photoelectric characteristics and the reverse intersystem crossing (RISC) process in organic light emitting diodes (OLEDs). Transient electroluminescence (EL) measurements indicated large contributions of triplet-triplet annihilation (TTA) for MADN but almost no contribution of TTA for PPBA. The magnetic field dependence of EL for the two anthracene compounds was also different. The EL of MADN was sensitive to the magnetic field at high current density, but PPBA showed less dependence, which indicated the absence of the TTA process for PPBA. TD-DFT calculations revealed that PPBA has doubly degenerate lowest triplet states (T1 and T2) with a much lower energy than S1, which is unfavorable for thermally activated delayed fluorescence (TADF). The near-zero ΔEST between highly excited states Sm≥1 and Tn>2 is favorable to RISC at a highly excited state. Oxygen quenching of photoluminescence only for PPBA and decreasing EL intensity with decreasing temperature only for PPBA support the existence of the RISC path from Tn>2 to Sm≥1. A high external quantum efficiency of 11% in blue OLEDs with PPBA was obtained, indicating that this orthogonal anthracene type of molecular design for RISC at a highly excited state would expand the material development of compounds emitting blue fluorescence for OLEDs.
- Pu, Yong-Jin,Satake, Rei,Koyama, Yuki,Otomo, Takahiro,Hayashi, Rika,Haruta, Naoki,Katagiri, Hiroshi,Otsuki, Daisuke,Kim, Daegwi,Sato, Tohru
-
supporting information
p. 2541 - 2547
(2019/03/08)
-
- A thiadiazole compound, a compound for a light-emitting element, light-emitting element, the light emitting device, the authentication device and electronic device
-
PROBLEM TO BE SOLVED: To provide a thiadiazole compound, a compound for light-emitting elements, and a light-emitting element capable of emitting light in the near-infrared region and having high efficiency and long life, and a light-emitting device, an authentication device, and an electronic device having the light-emitting element.SOLUTION: The thiadiazole compound is represented by the following formula (1), wherein Xs each independently represent a hydrogen atom or a functional group, and a ring may be formed by adjacent two or more Xs.
- -
-
Paragraph 0147
(2017/07/23)
-
- THIADIAZOLE-BASED COMPOUND, LIGHT EMITTING ELEMENT COMPOUND, LIGHT EMITTING ELEMENT, LIGHT EMITTING DEVICE, AUTHENTICATION DEVICE, AND ELECTRONIC DEVICE
-
Provided is a thiadiazole compound with high efficiency and long life which emits light in a near-infrared region and represented by Formula (I). [In the Formula (I), As each independently represent an aryl group which may have a substituent or a diarylamino group.]
- -
-
Page/Page column 50
(2012/11/07)
-
- The Multiplicity of Reaction Pathways of Cation Radicals Derived from Anthracene Derivatives in Solvents of Low Nucleophilicity
-
In acetonitrile containing trifluoroacetic acid, the cation radicals of 9-substituted anthracenes either dimerize (a), react with acetonitrile (b) or react with trifluoroacetic acid (c) depending on the nature of 9-substituent.All three reaction pathways were demonstrated during kinetic and product studies.Pathway (a) is of importance when the intermediate dimeric dication, which has both the substituents and the charges in the 10,10'-positions, is stabilized by virtue of the electron donating properties of the substituent.This pathway was observed exclusively for 9-phenyl and 9-methoxy and to a lesser extent when the substituent was 9-chloro.Pathway (c) predominantes when the 9-substituent destabilizes the positive charge as is the case for 9-nitro.The intermediate case (b) is the predominant reaction pathway for the anthracene cation radical and is also observed when the substituent is 9-methyl.The feature of pathway (b) differs most from (c) is that the intermediate cation radical-nucleophile adduct in (b) is charged and if the substituent is electron withdrawing the oxidation of this species by cation radical is less favorable so that trifluoroacetylation (c) can then effectively complete.All three of the reaction pathways were observed to give rise to complex rate laws.
- Hammerich, Ole,Parker. Vernon D.
-
p. 519 - 528
(2007/10/02)
-