An asymmetric supercapacitor (ASC) was assembled by using an activated carbon as positive electrode and WO3 nanowire as negative electrode, and its electrical performances were tested in voltage windows ranging from 0 to 1.5 V. A high specific capacitance of 51 F•g−1 could be achieved at the current density of 0.25 A•g−1. Moreover, the ASC displays a good cycling stability with 86% of capacitance retention after 800 cycles, its energy density can be up to 11.9 Wh•kg−1 at the power density of 210 W•kg−1, and remains 7.7 Wh•kg−1 at a power density of 1250 W• kg−1. The excellent electrical performance is perhaps due to the crystal orientation of (001) planes for the WO3 nanowire, which favors the rapid reaction between W(VI) and H+ cations. This aqueous asymmetric WO3//AC supercapacitor is promising for practical applications due to its easy preparation of WO3.
A new cyclometalated platinum complex containing 2, 5-bis(naphthalene-1-yl)-1,3,4-oxadiazole ligand was synthesized and characterized. The UV-Vis absorptions and photoluminescent properties of the ligand and its platinum complex were investigated. A characteristic metal-ligand charge transfer absorption peak at 439 nm in the UV spectrum and a strong emission peak at 625 nm in the photoluminescence spectrum were observed for this complex in dichloromethane. Cyclic voltammtry (CV) analysis shows that the E HOMO (energy level of the highest occupied molecular orbital) and E LUMO (energy level of the lowest unoccupied molecular orbital) of the platinum complex are about −5.69 and −3.25 eV, respectively, indicating that the oxadiazole-based platinum complex has a potential application in electrophosphorescent devices used as a red-emitting material.
An iridium (Ⅲ) bis [(4,6-difluorophenyl)hexyloxy picolinate) was synthesized and characterized by 1 H NMR and elementary analysis in order to study the effect of ancillary ligand of the oxadiazole-based picolinic acid derivative on optophysical properties of its iridium complex, and further to obtain an iridium complex with highly-efficient blue emission. The thermal stability, UV absorption and photoluminescent properties of this iridium complex were investigated. Compared with iridium (Ⅲ) bis[(4,6-difluorophenyl)pyridinato-N, C 2 ](picolinate) reported as a highly-efficient blue electroluminescent material, this iridium complex bearing an oxadiazole-based picolinic acid derivative presents higher thermal stability, more intense UV absorption at 291 nm and similar photoluminescent spectrum peaked at 469 nm. This indicates that tuning ancillary ligand of picolinic acid with an oxadiazole unit can improve the optophysical properties of its iridium complex.
Photo-physical properties of iridium complexes bis(1-(2′,4′-difluorobiphenyl -4-yl)isoquinoline)iridium(III)(5-(4-(bis(4-methoxyphenyl)amino)phenyl)picolinic acid) used as phosphorescent dopant in polymer light-emitting devices with a blend ofpoly(9,9-dioctylfluorene) and 2-tert-butyl-phenyl-5-biphenyl-1,3,4-oxadiazole as a host matrix are investigated. The iridium complex exhibits distinct UV-vis absorption bands around 300–450 nm and intense red photoluminescent emissions peaked at around 618 nm in dichloromethane. The devices display a maximum external quantum efficiency of 4.8% and luminous efficiency of 3.1 cd·A−1 at current density of 3.2 mA·cm−2 with a dominant red emission peak around 620 nm and a shoulder around 660 nm. At 100 mA·cm−2, the devices still display a maximum external quantum efficiency as high as 3.9%.
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