A new Eu（III） complex, EuL3（phen）, was synthesized, where L is the abbreviation of de- protonated 1-（7-（tert-butyl）-9-ethyl-gH-carbazol-2-yl）-4,4,4-trifluorobutane-l,3-dione （HL）, phen is the abbreviation of...A new Eu（III） complex, EuL3（phen）, was synthesized, where L is the abbreviation of de- protonated 1-（7-（tert-butyl）-9-ethyl-gH-carbazol-2-yl）-4,4,4-trifluorobutane-l,3-dione （HL）, phen is the abbreviation of 1,10-phenanthroline. The Eu（III） complex was characterized by element analysis, IR, 1H NMR, UV-visible absorption spectroscopy, thermogravimetric anal- ysis （TGA）, and photoluminescence measurements （PL）. TGA shows that thermal stability of the complex is up to 325 ~C. PL measurement indicates that the Eu（III） complex exhibits intense red-emission and extends their excitation bands to visible region. LEDs device was successfully fabricated by precoating complex EuL3 （phen） onto 460 nm blue-emitting InGaN chip. The emission of device shows that the complex can act as red phosphor in combination with 460 nm blue-emitting chips. This europium complex based on 1-（7-（tert-butyl）-9- ethyl-9H-carbazol-2-yl）-4,4,4-trifluorobutane-l,3-dione is a kind of interesting red-emitting material excited by blue light, which could avoid the damage of excitation by UV light.展开更多
Two bipolar materials,2,5-bis(2-(9H-carbazole-9-yl)phenyl)-1,3,4-oxadiazole(o-CzOXD)and 2,5-bis(2-(3',6'-di-tert-butyl-9H-carbazole-9-yl)phenyl)-1,3,4-oxadiazole(tBu-o-CzOXD),were synthesized according to repo...Two bipolar materials,2,5-bis(2-(9H-carbazole-9-yl)phenyl)-1,3,4-oxadiazole(o-CzOXD)and 2,5-bis(2-(3',6'-di-tert-butyl-9H-carbazole-9-yl)phenyl)-1,3,4-oxadiazole(tBu-o-CzOXD),were synthesized according to reported methods.In parallel study,it was demonstrated that introduction of inert tert-butyl group improved material thermal stability,even though this modification only had a slight influence to the photophysical and electrochemical properties of these materials.A comparative study focusing on effects of heat treatment was carried out on the quartz glass substrates with vacuum deposited films containing one of the bipolar host doped with 6 wt%fac-tris(2-phenylpyridinato-N,C2’)iridium(Ir(ppy)3).Results show that when the two samples were heated,the absorption,emission,and photo images of the host:dopant system changed,with the o-CzOXD suffering more severe degradation under high temperature,which is consistent with their thermal stability.In addition,it was proved that the high temperature-annealed host:dopant system can enhance the emission of the dopant.This finding was used as a guideline to improve our device performance.We fabricated two types of phosphorescent organic light-emitting devices(PhOLEDs),one was based on o-CzOXD,the other was based on tBu-o-CzOXD.They had analogous structure.We investigated the effect of heat on device performance by selectively annealing.Although these two freshly prepared devices exhibited similar performance,when annealed at 90°C for 10 min,the OLEDs based on tBu-o-CzOXD showed significant performance enhancement,which can be attributed to the observation that annealing Ir(ppy)3 doped host can change film morphology and enhance the dopant emission.The maximum efficiencies of the freshly prepared tBu-o-CzOXD device were 25.8 cd A-1,23.1lm W-1,and 9.3%;whereas those for annealed device were 47.0 cd A-1,42.2 lm W-1,and 13.4%.展开更多
文摘A new Eu（III） complex, EuL3（phen）, was synthesized, where L is the abbreviation of de- protonated 1-（7-（tert-butyl）-9-ethyl-gH-carbazol-2-yl）-4,4,4-trifluorobutane-l,3-dione （HL）, phen is the abbreviation of 1,10-phenanthroline. The Eu（III） complex was characterized by element analysis, IR, 1H NMR, UV-visible absorption spectroscopy, thermogravimetric anal- ysis （TGA）, and photoluminescence measurements （PL）. TGA shows that thermal stability of the complex is up to 325 ~C. PL measurement indicates that the Eu（III） complex exhibits intense red-emission and extends their excitation bands to visible region. LEDs device was successfully fabricated by precoating complex EuL3 （phen） onto 460 nm blue-emitting InGaN chip. The emission of device shows that the complex can act as red phosphor in combination with 460 nm blue-emitting chips. This europium complex based on 1-（7-（tert-butyl）-9- ethyl-9H-carbazol-2-yl）-4,4,4-trifluorobutane-l,3-dione is a kind of interesting red-emitting material excited by blue light, which could avoid the damage of excitation by UV light.
基金supported by the National Natural Science Foundation of China(61077021,61076016)the National Basic Research Program of China(2009CB930600)the Funding from Nanjing University of Posts and Telecommunications(NY212076,NY212050)
文摘Two bipolar materials,2,5-bis(2-(9H-carbazole-9-yl)phenyl)-1,3,4-oxadiazole(o-CzOXD)and 2,5-bis(2-(3',6'-di-tert-butyl-9H-carbazole-9-yl)phenyl)-1,3,4-oxadiazole(tBu-o-CzOXD),were synthesized according to reported methods.In parallel study,it was demonstrated that introduction of inert tert-butyl group improved material thermal stability,even though this modification only had a slight influence to the photophysical and electrochemical properties of these materials.A comparative study focusing on effects of heat treatment was carried out on the quartz glass substrates with vacuum deposited films containing one of the bipolar host doped with 6 wt%fac-tris(2-phenylpyridinato-N,C2’)iridium(Ir(ppy)3).Results show that when the two samples were heated,the absorption,emission,and photo images of the host:dopant system changed,with the o-CzOXD suffering more severe degradation under high temperature,which is consistent with their thermal stability.In addition,it was proved that the high temperature-annealed host:dopant system can enhance the emission of the dopant.This finding was used as a guideline to improve our device performance.We fabricated two types of phosphorescent organic light-emitting devices(PhOLEDs),one was based on o-CzOXD,the other was based on tBu-o-CzOXD.They had analogous structure.We investigated the effect of heat on device performance by selectively annealing.Although these two freshly prepared devices exhibited similar performance,when annealed at 90°C for 10 min,the OLEDs based on tBu-o-CzOXD showed significant performance enhancement,which can be attributed to the observation that annealing Ir(ppy)3 doped host can change film morphology and enhance the dopant emission.The maximum efficiencies of the freshly prepared tBu-o-CzOXD device were 25.8 cd A-1,23.1lm W-1,and 9.3%;whereas those for annealed device were 47.0 cd A-1,42.2 lm W-1,and 13.4%.
