给体-受体-给体窄带隙染料掺杂聚芴发光二极管

Donor-acceptor-donor Type Narrow-band-gap Dyes Doped Polyfluorene Light Emitting Diodes

合成了一系列给体-受体-给体型窄带隙荧光分子,并将其作为掺杂剂与主体(Host)宽带隙聚芴共混制备发光二极管.荧光分子为4,7-二呋喃-苯并噻二唑(O-S)、4,7-二噻吩-苯并噻二唑(S-S)、4,7-二(N-甲基吡咯)-苯并噻二唑(N-S)、4,7-二硒吩-苯并噻二唑(Se-S)和4,7-二(N-甲基吡咯)-苯并硒二唑(N-Se).溶液中荧光分子的紫外-可见吸收峰位于447～472nm,荧光发射峰位于563～637nm.该系列荧光分子掺杂聚芴(PFO)发光器件的电致发光峰位于580～633nm.当器件结构为ITO/PEDOT/PVK/PFO+N-Se/Ba/Al时,最大外量子效率为1.28%,电流效率1.31cd/A.

A series of donor-acceptor-donor（DAD） type narrow-band-gap fluorescent organic dyes were used as dopants for polymer light emitting diodes.The solutions of the organic molecules show absorbance peaks between 447 and 472 nm.The optical band gap decreases in the order：O-S and S-S N-S Se-S N-Se.The PL emission peak is around 563—637 nm depending on chemical structure.Energy transfer from polyfluorene to fluorescent organic dyes was observed for both photoluminescence and electroluminescence（EL） of the fluorescent dyes and polyfluorene composite film.The EL peak red shifted in the order are O-S,S-S,N-S,Se-S and N-Se,which agree with the optical band gap.The highest external quantum efficiency achieved with the device configuration ITO/PEDOT/PVK/PFO ＋ N-Se/Ba/Al is 1.28% with luminous efficiency 1.31 cd/A peaked at 633 nm.