Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (07): 1934-1940.doi: 10.3866/PKU.WHXB20100739

• PHOTOCHEMISTRY AND SPECTROSCOPY • Previous Articles     Next Articles

Synthesis and Spectral Stability of Blue Eletroluminescent Fluorene-Substituted Polyfluorenes

ZHANG Long, LIN Zong-Qiong, GU Ju-Fen, YIN Cheng-Rong, HOU Xiao-Ya, LIU Feng, LIU Yu-Yu, XIE Ling-Hai, CHEN Shu-Fen, HUANG Wei   

  1. Laboratory for Organic Electronics and Information Displays, Nanjing 210046, P. R. China
    Institute of Advanced Materials, Nanjing University of Posts and Telecommunication, Nanjing 210046, P. R. China
  • Received:2010-02-04 Revised:2010-05-04 Published:2010-07-02
  • Contact: XIE Ling-Hai, HUANG Wei E-mail:iamlhxie@njupt.edu.cn; iamwhuang@njupt.edu.cn

Abstract:

A monomer of diarylfluorene containing triphenylamine and dialkylfluorene groups at the 9-position and its copolymers, TPAFF-co-F and TPAFF-co-P, were successfully synthesized by a Suzuki cross-coupling polycondensation to obtain stable and highly efficient blue light-emitting polymers. The dialkylfluorenes on the polyfluorene chain served as an antioxidant function as well as a shielding effect. Triphenylamine groups are favorable for hole-injection at the ITO/emitting-layer interface. The combination impart good thermal, morphological and spectral stabilities. Annealing experiments for 24 h in air at 200 ℃show that the sequence of green indexes (Igreen/Iblue) decreases as follows: poly(9,9-dioctylfluorene) (1.07)>TPAFF-co-F(0.65) >TPAFF-co-P (0.47). These results indicate that dialkylfluorene plays a role in the antioxidant function. Devices were fabricated with the following configuration: ITO/PEDOT:PSS(40 nm)/TPAFF-co-F or TPAFF-co-P(80 nm)/Ba(4 nm)/Al (120 nm). Preliminary results confirmed that they have stable electroluminescent spectra with Commission Internationale d'Eclairage (CIE) coordinates of (0.22, 0.24) at a current density of 547 mA·cm-2 for TPAFF-co-F and a CIE of (0.24, 0.26) for TPAFF-co-P with a maximumcurrent efficiency of 0.712 cd·A-1.

Key words: Polyfluorene, Diarylfluorene, Low-energy emission band, Electroluminescence, Polymer blue light-emitting devices

MSC2000: 

  • O644