期刊
POLYMER
卷 241, 期 -, 页码 -出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.polymer.2021.124474
关键词
Covalent organic framework; sp(2) -carbon-linkage ; Tetraphenylethylene; White light-emitting diode; Phosphor
资金
- National Natural Science Foundation of China of China [21762049, 21262046]
- Open Fund for KeyLab of Guangdong High Property and Functional Macromolecular Materials, China [20190009]
- Education Department of Yunnan Province, China [2021Y658]
A sp(2)-carbon-linked covalent organic framework (COF) containing tetraphenylethene units was successfully synthesized. The COF exhibited a dual-pore eclipsed Kagome structure (AA-K) and high thermal stability. It was found that the COF could serve as promising metal-free phosphors in white light-emitting diodes (WLEDs), with different correlated color temperature (CCT) options achieved by varying the concentration.
A sp(2)-carbon-linked covalent organic framework (COF) containing tetraphenylethene units was successfully synthesized by using 2,2'-(1,4-phenylene)diacetonitrile and 4',4 '',4 '' ',4 '''' ''''-(Ethene-1,1,2,2-tetrayl)tetrakis (([1,1'-biphenyl]-4-carbaldehyde)) as monomers. After being investigated by powder X-Ray diffraction (PXRD), nitrogen adsorption-desorption and theoretical calculations, the dual-pore eclipsed Kagome structure (AA-K) of the COF was confirmed. The COF emitted bright yellow light with a solid-state photoluminesce quantum yield (PLQY) of 39.2%. It exhibited high thermal stability with a thermal decomposition temperature (Td) of ca. 610 ?, and its relative emission intensity at 90 ? was nearly 80.0% of that at 30 ?. The COF was blended in epoxy resin at different concentrations and used as phosphors, excited by GaN-based blue-emitting chips (lambda em,max & AP; 455 nm), a series of white light-emitting diodes (WLEDs) with different correlated color temperature (CCT) can be obtained. At 1.5 wt%, a cold WLED was obtained, its CCT was 6125 K, color rendering index (CRI) was 83.4, Commission Internationale de L'Eclairage (CIE) chromaticity coordinate was (0.32, 0.29), luminous efficiency (eta(L)) was 20.31 lm.W-1. At 2.0 wt%, a neutral WLED was obtained, its CCT was 4293 K, CRI was 79.6, chromaticity coordinate was (0.36, 0.34) and eta L was 19.71 lm.W-1. At 2.5 wt%, a warm WLED was obtained, its CCT was 3348 K, CRI was 69.4, chromaticity coordinate was (0.42, 0.42) and eta(L) was 18.81 lm(-1)W(-1). The results suggested the COF can be used promising metal-free phosphors in WLEDs.
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