2350-01-8Relevant articles and documents
Small-molecule azomethines: Organic photovoltaics via Schiff base condensation chemistry
Petrus,Bouwer,Lafont,Athanasopoulos,Greenham,Dingemans
, p. 9474 - 9477 (2014)
Conjugated small-molecule azomethines for photovoltaic applications were prepared via Schiff base condensation chemistry. Bulk heterojunction (BHJ) devices exhibit efficiencies of 1.2% with MoOx as the hole-transporting layer. The versatility and simplicity of the chemistry is illustrated by preparing a photovoltaic device directly from the reaction mixture without any form of workup. This journal is the Partner Organisations 2014.
Enhanced lifetime of organic light-emitting diodes using an anthracene derivative with high glass transition temperature
Lee, Seung-Hun,Kim, Sung Hyun,Kwak, Jeonghun
, p. 4216 - 4222 (2013)
Highly stable and efficient phosphorescent organic light-emitting diodes (OLEDs) were demonstrated by using anthracene-based hole injection buffer layer possessing high glass transition temperature. We synthesized a new anthracene derivative, 9,10-bis(3,3′-(N′,N′-diphenyl-(Nnaphthalene- 2-yl)benzene-1,4-diamine) phenyl)anthracene (TANPA) and characterized its optical and thermal properties. It showed high glass transition temperature of 154 °C which could be attributed to the insertion of anthracene into the aromatic amino group with triphenylamine. We also utilized TANPA for the hole injection and transport layers in phosphorescent OLEDs. Since TANPA has high glass transition temperature, the OLEDs using this material exhibited higher operational stability compared to the device without TANPA. When we use TANPA as the hole injection layer in combination with a widely-used hole transporting material, N,N′-di(1-naphthyl)-N,N-diphenylbenzidine (NPB), the devices showed high enhancement in terms of the operational lifetime, driving voltage change, and device efficiency, originating from the electron-hole charge balance as well as good thermal stability of TANPA. Copyright
Conjugated donor-acceptor-acceptor (D-A-A) molecule for organic nonvolatile resistor memory
Dong, Lei,Li, Guangwu,Yu, An-Dih,Bo, Zhishan,Liu, Cheng-Liang,Chen, Wen-Chang
, p. 3403 - 3407 (2014)
A new donor-acceptor-acceptor (D-A-A) type of conjugated molecule, N-(4-(N′,N′-diphenyl)phenylamine)-4-(4′-(2,2-dicyanovinyl)phenyl) naphthalene-1,8-dicarboxylic monoimide (TPA-NI-DCN), consisting of triphenylamine (TPA) donors and naphthalimide (NI)/dicyanovinylene (DCN) acceptors was synthesized and characterized. In conjunction with previously reported D-A based materials, the additional DCN moiety attached as end group in the D-A-A configuration can result in a stable charge transfer (CT) and charge-separated state to maintain the ON state current. The vacuum-deposited TPA-NI-DCN device fabricated as an active memory layer was demonstrated to exhibit writeonce- read-many (WORM) switching characteristics of organic nonvolatile memory due to the strong polarity of the TPA-NI-DCN moiety.
Non-doped organic light-emitting diodes based on phenanthroimidazole-triphenylamine derivatives with a low efficiency roll-off of 9% at a high luminance of 10?000 cd m-2
Du, Chunya,Feng, Zijun,Gao, Lei,He, Xin,Jiang, Dongyan,Liu, Futong,Liu, Hui,Lu, Ping
, p. 14446 - 14452 (2020)
Simultaneously achieving high exciton utilization efficiency (ηS) and a low efficiency roll-off at high brightness is challenging for fluorescent organic light-emitting diodes (OLEDs). In this work, we tried to realize this goal by constructing "hot exciton"materials by fine-tuning the lowest triplet excited state (T1) features. Two phenanthroimidazole-triphenylamine based donor-acceptor (D-A) derivatives TPPI-AQ and TPPI-BZPCN have been designed and synthesized. The photophysical studies and theoretical calculations reveal that TPPI-BZPCN has an obvious "hot exciton"feature and an aggregation-induced emission (AIE) characteristic. A big gap between T1 and T2 exists in TPPI-BZPCN which provides the possibility for a reverse intersystem system crossing (RISC) process from the upper energy level of T2 to S1. As a result, the non-doped electroluminescent device based on TPPI-BZPCN achieves a maximum external quantum efficiency (EQE) of 3.33%. The electroluminescence (EL) spectrum exhibits an emission peak at 592 nm, and the brightness can be up to 55?657 cd m-2. Also, the device is able to retain an EQE of 3.03% at the high luminance of 10?000 cd m-2, with a very low efficiency roll-off of 9%, which is the lowest efficiency roll-off currently reported in the orange-red emitters based on the "hot exciton"mechanism. Moreover, the ηS of the non-doped device reaches 48%, which exceeds the limitation of 25% in conventional fluorescence OLEDs.
Emergence of Aggregation Induced Emission (AIE), Room-Temperature Phosphorescence (RTP), and Multistimuli Response from a Single Organic Luminogen by Directed Structural Modification
Chatterjee, Abhijit,Chatterjee, Joy,Sappati, Subrahmanyam,Sheikh, Tariq,Umesh, Rintu M.,Ambhore, Madan D.,Lahiri, Mayurika,Hazra, Partha
, p. 12832 - 12846 (2021/11/24)
Multifunctional organic luminogens exhibiting simultaneous aggregation induced emission (AIE), room-temperature phosphorescence (RTP), and mechanochromism have recently attracted considerable attention owing to their potential applications in optoelectronics and bioimaging. However, a comprehensive correlation among these three distinguished properties is yet to be unveiled, which will help to decipher defined methodologies to design future generation multifunctional organic materials. Herein, we have demonstrated a route to obtain a multifunctional organic luminogen, starting from an ACQphore (TPANDI) by simple structural engineering. We have shown that a slight reduction in length of the planar acceptor moieties can effectively inhibit the undesirable π-πstacking interaction between molecules in the condensed state and thereby cause an ACQ to AIE type transformation from TPANDI to TPANMI and TPAPMI. Both TPANMI and TPAPMI exhibit RTP properties (even in ambient condition) because of the presence of a reasonably low singlet-triplet energy gap (δEST). In our study, these two luminogens were found to be mechano-inactive. Interestingly, an insertion of cyano-ethylene group and benzene linker in between the triphenylamine and phthalimide moieties introduced another luminogen TPACNPMI, which can simultaneously exhibit AIE, RTP, and mechanochromic properties.