화학공학소재연구정보센터
Journal of Polymer Science Part A: Polymer Chemistry, Vol.57, No.2, 171-182, 2019
Deep-blue light-emitting polyfluorenes with asymmetrical naphthylthio-fluorene as Chromophores
A novel blue polycyclic aromatic compound 2,8-dibromo-14,14-dioctyl-14H-benzo[b]benzo [5,6] fluoreno[1,2-d]thiophene 9,9-dioxide (Br2NFSO) is designed and synthesized through multistep synthesis, and its structure is confirmed by nuclear magnetic resonance. Based on synthesized polycyclic aromatic compound Br2NFSO, a series of twisted blue light-emitting polyfluorenes derivatives (PNFSOs) are prepared by one-pot Suzuki polycondensation. Based on the twisted polymer molecular structure resulted from the asymmetric links of 14,14-dioctyl-14H-benzo[b]benzo[5,6]fluoreno[1,2-d]thiophene 9,9-dioxide (NFSO) unit in copolymers and better electron transport ability of NFSO than those of the electron-deficient dibenzothiophene-S,S-dioxide counterpart, the resulting polymers exhibit excellent electroluminescent spectra stability in the current densities from 100 to 800 mA cm(-2), and show blue-shifted and narrowed electroluminescent spectra with the Commission Internationale de L ' Eclairage (CIE) of (0.16, 0.07) for PNFSO5, compared to poly(9,9-dioctylfluorene) (PFO) with the CIE of (0.18, 0.18). Moreover, the superior device performance is achieved based on PNFSO5 with the maximum luminous efficiency (LEmax) of 1.96 cd A(-1), compared with the LEmax of 0.49 cd A(-1) for PFO. The results indicate that the twisted polycyclic aromatic structure design strategy has a great potential to tuning blue emission spectrum and improving EL efficiency of blue light-emitting polyfluorenes. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 171-182