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Mao Z.,Sun Yat Sen University | Yang Z.,Sun Yat Sen University | Zhang Y.,Sun Yat Sen University | Wang Y.-F.,Shenzhen China Star Optoelectronics Technology Co. | And 5 more authors.
Angewandte Chemie - International Edition | Year: 2015

Organic mechanoluminochromic materials are mechano/piezo-responsive and promising for applications in sensors, displays, and data storage devices. However, their switching range of emission is seriously impeded by only one kind of emission (either a fluorescent or phosphorescent peak) in the spectrum of single organic compounds. This study presents a design strategy for pure organic compounds with excellent room-temperature fluorescent-phosphorescent dual-emission (rFPDE) properties, which combines the effective factors of dipenylsulfone group, crystalline state, and heavy atom effect. Following the principle of color mixing, myriad emission colors with a wide range from orange to purple and across white zone in a straight line in the chromaticity diagram of the Commission Internationale de l'Eclairage (CIE) can be obtained by simply mechanical grinding the compound. The unique properties could be concentrated on a pure organic compound through this design strategy, which provides a new efficient channel for the discovery of efficient mechano-responsive organic materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Lien A.,TCL Corporate Research
Digest of Technical Papers - SID International Symposium | Year: 2015

We have investigated a photo alignment material for fringe field switching (FFS) liquid crystal display and it has good alignment performance. It realizes alignment by irradiating linearly polarized light with wavelength of254nm. We have investigated the factors that affect the transmittance in photo alignment FFS mode. The transmittance becomes smaller with the alignment angle increasing. The transmittance is also affected by the L/S width of the ITO electrode, it becomes smaller with the US increasing. The LC type also affect the transmittance, we can get higher transmittance using negative LC. © 2015 SID. Source


Lien A.,TCL Corporate Research
Digest of Technical Papers - SID International Symposium | Year: 2015

A new photo alignment material for fringe field switching (FFS) and in-plane switching (IPS) liquid crystal display has been presented and it has good alignment performance. It realizes alignment by irradiating linearly polarized light with wavelength of 365nm. We have investigated the effect of UV dosage and anneal process on the alignment ability and optical performance. An excellent dark state and image sticking property can be achieved by optimized photo alignment conditions. © 2015 SID. Source


Ye H.,South China University of Technology | Chen D.,South China University of Technology | Liu M.,South China University of Technology | Su S.-J.,South China University of Technology | And 4 more authors.
Advanced Functional Materials | Year: 2014

A series of pyridine-containing electron-transport materials are developed as an electron-transport layer for the FIrpic-based blue phosphorescent organic light-emitting diodes. Their energy levels can be tuned by the introduction of pyridine rings in the framework and on the periphery of the molecules. Significantly reduced operating voltage is achieved without compromising external quantum efficiency by solely tuning the nitrogen atom orientations of those pyidine rings. Unprecedented low operating voltages of 2.61 and 3.03 V are realized at 1 and 100 cd m-2, giving ever highest power efficiency values of 65.8 and 59.7 lm W-1, respectively. In addition, the operating voltages at 100 cd m-2 can be further reduced to 2.70 V by using a host material with a small singlet-triplet exchange energy, and the threshold voltage for electroluminescence can even be 0.2-0.3 V lower than the theoretical minimum value of the photon energy divided by electron charge. Aside from the reduced operating voltage, a further reduced roll-off in efficiency is also achieved by the combination of an appropriate host material. Unprecedented low operating voltages are realized for the FIrpic-based blue phosphorescent OLEDs by using pyridine-containing electron-transport materials, giving ever highest power efficiencies of 65.8 and 59.7 lm W-1 at 1 and 100 cd m-2, respectively. The threshold voltage for electroluminescence can be 0.2-0.3 V lower than the minimum value of hv/e by using a host material with low ΔEST. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Li X.-L.,South China University of Technology | Ye H.,South China University of Technology | Chen D.-C.,South China University of Technology | Liu K.-K.,South China University of Technology | And 7 more authors.
Israel Journal of Chemistry | Year: 2014

A series of triazole and pyridine hybrid molecules, with a triazole core and pyridine periphery, were designed and synthesized as an electron-transport layer (ETL) and a hole/exciton-block layer for green phosphorescent organic light-emitting diodes. Compared with the widely-used electron-transport material (ETM) of 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ) with a triazole core, lower-lying HOMO and LUMO energy levels were obtained with the introduction of pyridine rings onto the periphery of the molecules, giving improved electron injection and carrier confinement. Significantly reduced driving voltages were achieved in a device structure of ITO/HATCN (5 nm)/TAPC (40 nm)/CBP:8 wt % Ir(PPy)3 (10 nm)/ETL (40 nm)/LiF (1 nm)/Al (90 nm), giving a maximum power efficiency of 72.2 lm W -1 and an external quantum efficiency of 21.8 %, due to the improved electron injection and transport and thus, more balanced carrier recombination, which are much higher than those of the device based on TAZ. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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