On account of the advantages of organic electroluminescent materials compared with their inorganic counterparts,the development of organic electroluminescent materials is one of the hot areas of the optoelectronic mat...On account of the advantages of organic electroluminescent materials compared with their inorganic counterparts,the development of organic electroluminescent materials is one of the hot areas of the optoelectronic materials.Fluorene and its derivatives,which have an aromatic biphenyl structure with a wide energy gap in the backbones and high luminescent efficiency,have drawn much attention of ma-terial chemists and device physicists.However,one drawback of fluorene-based electroluminescent blue materials is that there is an occurrence of long wavelength emission after annealing the films in air or after operating organic light-emitting diodes for a long time.To clarify the origin of this long wave-length emission,the scientists at home and abroad have put forward all kinds of correlative explana-tions.Among the scientists,some thought it was caused by excimer-related species,while some others claimed that it was caused by the fluorenone of photooxdized fluorene.The corresponding solutions to this problem have also been proposed and the problem has been partially resolved in some degree.The present review summarizes and analyzes the progress made on the origin of long wavelength emission in fluorene-based electroluminescent blue materials at home and abroad in the past few years.Some issues to be addressed and hotspots to be further investigated are also presented and discussed.展开更多
Because organic conjugated materials offer several advantages relative to their inorganic counterparts,the development of organic conjugated materials has been one of the most active research areas in optoelectronic m...Because organic conjugated materials offer several advantages relative to their inorganic counterparts,the development of organic conjugated materials has been one of the most active research areas in optoelectronic materials.For almost two decades,the search for organic conjugated materials has represented a major driving force for research concerned with controlling the band gap of extended π-conjugated molecules.In particular,among the parameters affecting the performance of organic light-emitting diodes (OLEDs),the energy levels of organic conjugated materials play an important role because they can affect the driving voltage,wavelength,efficiency,and lifetime of the final device.Balanced injection and transport of electrons and holes are therefore crucial for achieving OLEDs with high quantum efficiency.In this regard,research into adjusting the energy levels of organic conjugated materials is very meaningful for the development of OLEDs.To adjust the energy levels of the organic conjugated materials,Huang et al.have presented a new molecular design and synthesis route that yields p-n diblock conjugated copolymers and oligomers.The present review summarizes and analyzes the progress on adjusting the optoelectronic properties of organic conjugated materials that is due to synthesizing p-n diblock molecules.We discusses primarily work done by Huang et al.,but also discusses work done elsewhere over the past few years.We also point out issues that require attention,and highlight hot spots that require further investigation.展开更多
Here,9,9.9'-tris(4-butoxyphenyl)-9H-9'Hl-2,2'-difluorene(DF)was synthesized as a reference for compa rison,and diphenyl sulfone and triphenylphosphine oxygen were introduced to the 9-position of fluorene t...Here,9,9.9'-tris(4-butoxyphenyl)-9H-9'Hl-2,2'-difluorene(DF)was synthesized as a reference for compa rison,and diphenyl sulfone and triphenylphosphine oxygen were introduced to the 9-position of fluorene througha C-H coupling reaction to produce two fluorene-based oligomers 9′,9′″-sulfonylbis(4.1-phenylene)bis9,9′,9′tris(4-butoxyphenyl)-9H,9'H-2.2'-bifluorene(DF)SOz and phenylbis(4-{9.9,9-tris(4-butoxyphenyl)-9H,9'H-12.2-bif-luorenel-9-yl} phenyl)phosphine oxidel(DF)2POI.Solid powders of all the three compounds exhibit excellent therma stability with thermal temperature at 5%mass loss of 375,429 and 383 C for(DF)2SO2,(DF)PO and DF.In addition,owing to the distorted molecular structure and weak electron-absorbing ability of the acceptor,(DF)Soz and(DF)2PO do not have obvious intramolecular charge transfer characteristics.and exhibit stable localized 394 nm/375 nm fluorescence emission peaks in different polar solvents.The absolute luminescence quantumefficiencies of(DF)2S02,(DF)PO and DF solid powders are 20.83%,10.03%and 59.46%,Compound DF has the highest quantum yield as an electron donor.The chromaticity coordinates of the blue OLED devices based on DF and DF2SO2 fabricated by solution spin coating were(0.19.0.10)and(0.19.0.11).which were closest to the deep blue region,and the corresponding maximum external quantum efficiencies are 1.45%and 0.87%,respectively,which are higher than that of(DF)2PO(0.25%)and consistent with the difference in the solid-state quantum efficiency between them.展开更多
基金the National Natural Science Foundation of China(Grant Nos:90406021,20774043and20574012)Natural Science Foundation of Jiangsu College Council(Grant No:KJD150148)Scientific Research Foundation of Nanjing University of Posts and Telecommunications(Grant No:NY206069)
文摘On account of the advantages of organic electroluminescent materials compared with their inorganic counterparts,the development of organic electroluminescent materials is one of the hot areas of the optoelectronic materials.Fluorene and its derivatives,which have an aromatic biphenyl structure with a wide energy gap in the backbones and high luminescent efficiency,have drawn much attention of ma-terial chemists and device physicists.However,one drawback of fluorene-based electroluminescent blue materials is that there is an occurrence of long wavelength emission after annealing the films in air or after operating organic light-emitting diodes for a long time.To clarify the origin of this long wave-length emission,the scientists at home and abroad have put forward all kinds of correlative explana-tions.Among the scientists,some thought it was caused by excimer-related species,while some others claimed that it was caused by the fluorenone of photooxdized fluorene.The corresponding solutions to this problem have also been proposed and the problem has been partially resolved in some degree.The present review summarizes and analyzes the progress made on the origin of long wavelength emission in fluorene-based electroluminescent blue materials at home and abroad in the past few years.Some issues to be addressed and hotspots to be further investigated are also presented and discussed.
基金supported by the National Basic Research Program of China(2009CB930601)the Key Project of the Ministry of Education(104246)+2 种基金the National Natural Science Foundation of China(20774043,60706017 and 20574012)the Creative Research Group of Jiangsu College Council(TJ207035 and TJ209035)the Natural Science Foundation of Jiangsu College Council(10KJB150012)
文摘Because organic conjugated materials offer several advantages relative to their inorganic counterparts,the development of organic conjugated materials has been one of the most active research areas in optoelectronic materials.For almost two decades,the search for organic conjugated materials has represented a major driving force for research concerned with controlling the band gap of extended π-conjugated molecules.In particular,among the parameters affecting the performance of organic light-emitting diodes (OLEDs),the energy levels of organic conjugated materials play an important role because they can affect the driving voltage,wavelength,efficiency,and lifetime of the final device.Balanced injection and transport of electrons and holes are therefore crucial for achieving OLEDs with high quantum efficiency.In this regard,research into adjusting the energy levels of organic conjugated materials is very meaningful for the development of OLEDs.To adjust the energy levels of the organic conjugated materials,Huang et al.have presented a new molecular design and synthesis route that yields p-n diblock conjugated copolymers and oligomers.The present review summarizes and analyzes the progress on adjusting the optoelectronic properties of organic conjugated materials that is due to synthesizing p-n diblock molecules.We discusses primarily work done by Huang et al.,but also discusses work done elsewhere over the past few years.We also point out issues that require attention,and highlight hot spots that require further investigation.
基金Supported by the National Natural Science Foundation of China(No.21574068)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(No.YX030003).
文摘Here,9,9.9'-tris(4-butoxyphenyl)-9H-9'Hl-2,2'-difluorene(DF)was synthesized as a reference for compa rison,and diphenyl sulfone and triphenylphosphine oxygen were introduced to the 9-position of fluorene througha C-H coupling reaction to produce two fluorene-based oligomers 9′,9′″-sulfonylbis(4.1-phenylene)bis9,9′,9′tris(4-butoxyphenyl)-9H,9'H-2.2'-bifluorene(DF)SOz and phenylbis(4-{9.9,9-tris(4-butoxyphenyl)-9H,9'H-12.2-bif-luorenel-9-yl} phenyl)phosphine oxidel(DF)2POI.Solid powders of all the three compounds exhibit excellent therma stability with thermal temperature at 5%mass loss of 375,429 and 383 C for(DF)2SO2,(DF)PO and DF.In addition,owing to the distorted molecular structure and weak electron-absorbing ability of the acceptor,(DF)Soz and(DF)2PO do not have obvious intramolecular charge transfer characteristics.and exhibit stable localized 394 nm/375 nm fluorescence emission peaks in different polar solvents.The absolute luminescence quantumefficiencies of(DF)2S02,(DF)PO and DF solid powders are 20.83%,10.03%and 59.46%,Compound DF has the highest quantum yield as an electron donor.The chromaticity coordinates of the blue OLED devices based on DF and DF2SO2 fabricated by solution spin coating were(0.19.0.10)and(0.19.0.11).which were closest to the deep blue region,and the corresponding maximum external quantum efficiencies are 1.45%and 0.87%,respectively,which are higher than that of(DF)2PO(0.25%)and consistent with the difference in the solid-state quantum efficiency between them.
