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Anionic triphenylamine‐ and fluorene‐based conjugated polyelectrolyte as a hole‐transporting material for polymer light‐emitting diodes
Author(s) -
Shi Wei,
Wang Lei,
Huang Fei,
Liu Ransheng,
Yang Wei,
Cao Yong
Publication year - 2009
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.2541
Subject(s) - triphenylamine , polyelectrolyte , materials science , fluorene , copolymer , chemical engineering , polymer , polymer chemistry , polyfluorene , solvent , organic chemistry , chemistry , engineering , composite material
BACKGROUND: Hole‐transport layers (HTLs) play a crucial role in multilayer polymeric light‐emitting diodes (PLEDs) for the achievement of satisfactory device performance. During the fabrication of multilayer PLEDs via solution processing, the fabricated HTLs encounter the risk of erosion during the film‐forming process of subsequent emitting layers (EMLs). In contrast to the widely investigated crosslinkable HTLs, much less attention has been paid to the preparation of polar‐solvent‐soluble HTLs, which is a straightforward solution to overcome the interfacial mixing between HTLs and EMLs during solution processing. RESULTS: Alternating triphenylamine‐ and fluorene‐based anionic copolymer poly[9,9‐bis(4′‐sulfonatobutyl)fluorene‐ alt ‐ N ‐( p ‐trifluoromethyl)phenyl‐4,4′‐diphenylamine]sodium salt (PFT‐CF3) was synthesized via a palladium‐catalyzed Suzuki coupling reaction. This polyelectrolyte is soluble only in polar solvents such as methanol, dimethylformamide and dimethylsulfoxide rather than in non‐polar solvents such as toluene, chloroform and xylene. The relatively high HOMO (−5.22 eV) and LUMO (−2.26 eV) levels of this polymer endow it simultaneously with good hole‐transporting and electron‐blocking capabilities. The performance of red‐, green‐ and blue‐emitting devices utilizing this polyelectrolyte as HTL was investigated. CONCLUSION: The anionic conjugated polyelectrolyte based on triphenylamine and fluorene, PFT‐CF 3 , can serve as a promising hole‐transporting/electron‐blocking layer in multilayer PLEDs. Copyright © 2009 Society of Chemical Industry