Guangbo Che

Highly efficient and color-tuning electrophosphorescent devices based on CuI complex

Highly efficient electrophosphorescence from organic light-emitting devices based on a CuI complex, [Cu(DPEphos)(Dicnq)]BF4 (DPEphos=bis[2-(diphenylphosphino)phenyl]ether and Dicnq=6,7-Dicyanodipyrido[2,2-d:2′,3′-f] quinoxaline), doped into 4,4′-N,N′-dicarbazole-biphenyl is demonstrated. The performances of these devices fabricated by vacuum vapor deposition technique are among the best reported for devices incorporating CuI complexes as emitters. A low turn-on voltage of 4V, a maximum current efficiency up to 11.3cd∕A, and a peak brightness of 2322cd∕m2 were achieved, respectively. The phosphorescent operating mechanism of organic light-emitting devices based on CuI complex was discussed. Electroluminescent colors can be tuned ranging from green-yellow to orange-red region, and its band tail at longer wavelength can cover near infrared.

Hydrothermal Syntheses of Some Derivatives of Tetraazatriphenylene

Abstract Some derivatives of tetraazatriphenylene can be synthesized readily by a hydrothermal synthetic method. Compared with the traditional technique, this method is effective and simple process, and much high yields of products with higher purity can be harvested.

White-electrophosphorescent devices based on copper complexes using 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4-oxadiazole as chromaticity-tuning layer

Efficient white organic light-emitting diodes based on copper complex, [Cu(bis[2-(diphenylphosphino)phenyl]ether)(6,7-dicyanodipyrido[2,2-d:2′,3′‐f]quinoxaline)]BF4 [Cu(I) complex], in which the white emission composed of yellow emission from Cu(I) complex doped 4,4′‐N,N′-dicarbazole-biphenyl (CBP) layer and blue emission from N,N′-diphenyl-N,N′-bis(1-naphthyl)-(1,1′-benzidine)-4,4′-diamine layer, were fabricated. A thin 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4-oxadiazole (Bu-PBD) layer sandwiched between the two emission layers acts as a chromaticity-tuning layer. The white device with 10nm, 2wt% Cu(I) complex doped CBP layer and 2nm Bu-PBD layer shows CIE coordinates of (0.33,0.36) at applied bias of 10V, a maximum luminance of 2466cd∕m2, and a maximum current efficiency of 6.76cd∕A, corresponding to the power efficiency of 3.85lm∕W. The efficient white emission is attributed to the simultaneous exciton formation in both emission layer. The working mechanism of the thin Bu-PBD layer for achieving ...

Highly sensitive organic ultraviolet optical sensor based on phosphorescent Cu (I) complex

Ultraviolet light-sensitive organic optical sensor based on photovoltaic diode was demonstrated by using a phosphorescent Cu complex and a diamine derivative as electroacceptor and electrodonor, respectively. The Cu complex is Cu(DPEphos)((Bphen))BF4, in which DPEphos and Bphen denote 6,7-dicyanodipyrido [2,2-d:2′,3′-f] quinoxaline and bathophenanthroline. And the diamine derivative, m-MTDATA, is 4, 4′,4″-tris-(2-methylphenyl phenylamino) triphenylamine. The sensor is highly sensitive to UV light band from 300to420nm while it has almost no response to the visible light, and under illumination of 365nm light with power of 1.7mW∕cm2, the sensor exhibits an open circuit voltage of 1.86V, a short circuit current of 105.3μA∕cm2, a fill factor of 0.246, and a power conversion efficiency of 2.83%. The dependences of ultraviolet responsive sensitivity on illumination intensity and working temperature were also discussed.

Improved electroluminescent performances of europium-complex based devices by doping into electron-transporting/hole-blocking host

High-efficiency, pure red organic light-emitting devices were fabricated by doping a europium-complex Eu(DBM)3pyzphen (DBM=dibenzoylmethane, pyzphen=pyrazino[2,3-f][1,10]phenanthroline) into 4,7-diphenyl-1,10-phenanthroline as emission layer. A maximum current efficiency of 5.1cd∕A at the current density of 1.2mA∕cm2 and a maximum luminance of 1400cd∕m2 were obtained from a 25wt% Eu(DBM)3pyzphen doped device. High efficiencies were maintained at high current densities and high luminance. For example, at the current density of 10mA∕cm2, the efficiency reached 3.8cd∕A. It means that the efficiency roll-off, a major obstacle to the development of Eu-complex ogranic light-emitting devices, was greatly alleviated. The mechanisms behind the improvement are discussed.

Enhanced electrophosphorescence of copper complex based devices by codoping an iridium complex

Evidently enhanced electrophosphorescence of [Cu(bis[2-(diphenylphosphino)phenyl] ether)(6,7-dicyanodipyrido [2,2-d:2′,3′-f] quinoxaline)] BF4 (CuI complex) by codoping bis[(4,6-difluorophenyl)-pyridinato-N, C2](picolinato)Ir(III) (FIrpic) into the same host, 4,4′-N,N′-dicarbazole-biphenyl, was demonstrated. The device codoped with 8wt% FIrpic and 2wt% CuI complex shows a maximum current efficiency and power efficiency of 26.6cd∕A and 17.8lm∕W, respectively, which were increased by factors of 2.6 and 2.1 compared with the 2wt% CuI complex monodoped device. The improvements of the devices were testified to the efficient energy transfer from FIrpic to the CuI complex. The detail of the energy transfer mechanism between the two phosphors was also proposed.