Understanding the molecular gelation processes of heteroatomic conjugated polymers for stable blue polymer light-emitting diodes. Issue 27 (26th June 2017)

• Record Type: Journal Article
• Authors: Lin, Jin-Yi; Liu, Bin; Yu, Meng-Na; Ou, Chang-Jin; Lei, Zhen-Feng; Liu, Feng; Wang, Xu-Hua; Xie, Ling-Hai; Zhu, Wen-Sai; Ling, Hai-Feng; Zhang, Xin-Wen; Stavrinou, Paul N.; Wang, Jian-Pu; Bradley, Donal D. C.; Huang, Wei
• Is Part Of: Journal of materials chemistry. Volume 5:Issue 27(2017)
• Page Start: 6762
• Page End: 6770
• Publication Date: 2017-06-26
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7tc01541k
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Designing optoelectronic properties using heteroatomic conjugated polymers (HCPs). Abstract : Heteroatomic conjugated polymers (HCPs) can have complicated molecular structures with several heteroatoms in the repeat unit, which is helpful for designing color-tunable emitters, photovoltaic donors and high mobility materials. In order to understand their relatively complex molecular superstructure characteristics in depth, heteroatomic substitution-induced diverse non-covalent interactions must be investigated. Here, we systematically studied the gelation processing and its influence on the optoelectronic properties of a series of sp 2 nitrogen (N) substituted polyfluorenes (PF8- co -DAF8) towards highly stable blue polymer light-emitting diodes (PLEDs). This heteroatomic substitution allows for diverse chain C–H⋯N hydrogen bonds, correlating with an excellent gelation behavior at room temperature. Films with a gelation superstructure show a weak interchain π–π interaction and energy transfer compared to non-gelation ones. PLEDs based on a gelation film give a stable, deep-blue emission with CIE coordinates of (0.16, 0.17) and a luminous efficiency (L.E.) of 1.30 cd A −1, while non-gelation film-based PLEDs display a stable, sky-blue emission (CIE: 0.20, 0.24; L.E.: 2.13 cd A −1 ). Diverse non-covalent interactions originating from the heteroatomic substitution cause a complicated molecular aggregation behavior in solution that can significantly affect the chain rearrangement in the film-casting process, thereby dominating the optoelectrical properties.