89555-39-5Relevant articles and documents
Deep-blue light-emitting polyfluorenes with asymmetrical naphthylthio-fluorene as Chromophores
Hu, Liwen,Wu, Zhonglian,Wang, Xiaojun,Ma, Yawei,Guo, Ting,Ying, Lei,Peng, Junbiao,Cao, Yong
, p. 171 - 182 (2019)
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.
Efficient polyfluorene derivatives for blue light-emitting diodes enabled by tuning conjugation length of bulky chromophores
Guo, Feng,Hu, Liwen,Xiao, Biao,Yang, Renqiang,Ying, Lei,Zhang, Mingrui,Zhao, Sen
, (2022/01/06)
In this work, a series of blue chromophores containing PAH core with different conjugation lengths and end-capped with diphenylamine were developed and introduced into PPF derivatives. Since the blue chromophores can enhance the thermal stability and suppress the interchain interactions efficiently, all copolymers present outstanding thermal decomposition temperatures up to 425 °C, high photoluminescence quantum yields (PLQYs) up to 48% and smooth surface morphology. Furthermore, the corresponding single-layer blue polymer light-emitting devices (PLEDs) based on these blue copolymers show good blue light emission peaking at 456–468 nm, and excellent stability of electroluminescence (EL) spectra. In particular, the best PLED with a maximum luminance of 8938 cd m?2, a maximum luminous efficiency (LEmax) of 3.73 cd A?1, Commission International de L'Eclairage (CIE) coordinates of (0.14, 0.16) is achieved based on PPF-F. These results demonstrate that tuning the conjugation length of the bulky chromophores in blue light-emitting polymers is a novel and effective molecular design strategy toward highly stable and efficient blue polymer light-emitting diodes.
Synthesis and photophysical properties of isocoumarin-based D-π-A systems
Pirovano, Valentina,Marchetti, Marialaura,Carbonaro, Jessica,Brambilla, Elisa,Rossi, Elisabetta,Ronda, Luca,Abbiati, Giorgio
, (2019/09/30)
We prepared a small library of polarity-sensitive fluorescent dyes characterized by an isocoumarin core properly functionalized with a conjugated push-pull system. The key step of the synthesis is based on a regio-selective silver(I)/p-TSA co-catalyzed cyclization of 2-alkynylbenzoates recently optimized in our laboratory. The photophysical properties of isocoumarin-based D-π-A systems have been investigated and a rationale was proposed based on their dipole moments and Hammett constants of the ED and EW groups involved.
