Organic solid-state luminescent materials with high-efficiency deep-red emission have attracted considerable interest in recent years.Constructing donor-acceptor(D-A)type molecules has been one of most commonly used s...Organic solid-state luminescent materials with high-efficiency deep-red emission have attracted considerable interest in recent years.Constructing donor-acceptor(D-A)type molecules has been one of most commonly used strategies to achieve deep-red emission,but it is always difficult to achieve high photoluminescence(PL)quantum yield(ηPL)due to forbidden charge-transfer state.Herein,we report a new D-A type molecule 4-(7-(4-(diphenylamino)phenyl)-9-oxo-9H-fluoren-2-yl)benzonitrile(TPAFOCN),deriving from donor-acceptor-donor(D-A-D)type 2,7-bis(4-(diphenylamino)phenyl)-9H-fluoren-9-one(DTPA-FO)with a fluorescence maximum of 627 nm in solids.This molecular design enables a transformation of acceptor from fluorenone(FO)itself to 4-(9-oxo-9H-fluoren-2-yl)benzonitrile(FOCN).Compared with DTPA-FO,the introduction of cyanophenyl not only shifts the emission of TPA-FOCN to deep red with a fluorescence maximum of 668 nm in solids,but also maintains the highηPL of 10%.Additionally,a solution-processed non-doped organic light-emitting diode(OLED)was fabricated with TPA-FOCN as emitter.TPA-FOCN device showed a maximum luminous efficiency of 0.13 cd/A and a maximum external quantum efficiency(EQE)of 0.22%with CIE coordinates of(0.64,0.35).This work provides a valuable strategy for the rational design of high-efficiency deep-red emission materials using cyanophenyl as an ancillary acceptor.展开更多
A new approach to synthesize liquid crystalline polymer with narrow polydispersity index（PDI） was developed.Photopolymerization of 4-cyanophenyl-4＇-（6-acryloyloxyhexyloxy）benzoate（RM23） in nematic liquid crysta...A new approach to synthesize liquid crystalline polymer with narrow polydispersity index（PDI） was developed.Photopolymerization of 4-cyanophenyl-4＇-（6-acryloyloxyhexyloxy）benzoate（RM23） in nematic liquid crystals with macroscopic orientation was studied.The effects of the monomer concentration on the molecular weight and PDI of the resulting polymers were studied through gel permeation chromatography（GPC） and polarized optical microscopy.The low PDI of 1.19 and 1.22 was obtained in the reverse and normal modes,respectively.The PDI and molecular weight increased with monomer concentration.展开更多
基金supported by the National Natural Science Foundation of China(Nos.91833304,51873077,51803071 and51673083)the National Basic Research Program of China(Nos.2015CB655003 and 2016YFB0401001)+2 种基金the Postdoctoral Innovation Talent Support Project(Nos.BX201700097 and BX20180121)the China Postdoctoral Science Foundation(Nos.2017M620108 and2018M641767)JLUSTIRT(No.2019TD-33)
文摘Organic solid-state luminescent materials with high-efficiency deep-red emission have attracted considerable interest in recent years.Constructing donor-acceptor(D-A)type molecules has been one of most commonly used strategies to achieve deep-red emission,but it is always difficult to achieve high photoluminescence(PL)quantum yield(ηPL)due to forbidden charge-transfer state.Herein,we report a new D-A type molecule 4-(7-(4-(diphenylamino)phenyl)-9-oxo-9H-fluoren-2-yl)benzonitrile(TPAFOCN),deriving from donor-acceptor-donor(D-A-D)type 2,7-bis(4-(diphenylamino)phenyl)-9H-fluoren-9-one(DTPA-FO)with a fluorescence maximum of 627 nm in solids.This molecular design enables a transformation of acceptor from fluorenone(FO)itself to 4-(9-oxo-9H-fluoren-2-yl)benzonitrile(FOCN).Compared with DTPA-FO,the introduction of cyanophenyl not only shifts the emission of TPA-FOCN to deep red with a fluorescence maximum of 668 nm in solids,but also maintains the highηPL of 10%.Additionally,a solution-processed non-doped organic light-emitting diode(OLED)was fabricated with TPA-FOCN as emitter.TPA-FOCN device showed a maximum luminous efficiency of 0.13 cd/A and a maximum external quantum efficiency(EQE)of 0.22%with CIE coordinates of(0.64,0.35).This work provides a valuable strategy for the rational design of high-efficiency deep-red emission materials using cyanophenyl as an ancillary acceptor.
基金The authors are grateful to NSF of China(No.50703013)Independent Innovative Position of Hubei Province for financial support of this work
文摘A new approach to synthesize liquid crystalline polymer with narrow polydispersity index（PDI） was developed.Photopolymerization of 4-cyanophenyl-4＇-（6-acryloyloxyhexyloxy）benzoate（RM23） in nematic liquid crystals with macroscopic orientation was studied.The effects of the monomer concentration on the molecular weight and PDI of the resulting polymers were studied through gel permeation chromatography（GPC） and polarized optical microscopy.The low PDI of 1.19 and 1.22 was obtained in the reverse and normal modes,respectively.The PDI and molecular weight increased with monomer concentration.
