Thermally Activated Delayed Fluorescence Carbonyl Derivatives for Organic Light-Emitting Diodes with Extremely Narrow Full Width at Half-Maximum

Xing Li, Yi Zhong Shi, Kai Wang, Ming Zhang, Cai Jun Zheng, Dian Ming Sun, Gao Le Dai, Xiao Chun Fan, De Qi Wang, Wei Liu, Yan Qing Li, Jia Yu, Xue Mei Ou, Chihaya Adachi, Xiao Hong Zhang

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Abstract

Two novel thermally activated delayed fluorescence (TADF) emitters, 3-phenylquinolino[3,2,1-de]acridine-5,9-dione (3-PhQAD) and 7-phenylquinolino[3,2,1-de]acridine-5,9-dione (7-PhQAD), were designed and synthesized based on a rigid quinolino[3,2,1-de]acridine-5,9-dione (QAD) framework. With the effective superimposed resonance effect from electron-deficient carbonyls and electron-rich nitrogen atom, both emitters realize significant TADF characteristics with small ΔE ST s of 0.18 and 0.19 eV, respectively. And, molecular relaxations were dramatically suppressed for both emitters because of their conjugated structure. In the devices, 3-PhQAD realizes superior performance with a maximum external quantum efficiency (EQE) of 19.1% and a narrow full width at half-maximum (FWHM) of 44 nm, whereas a maximum EQE of 18.7% and an extremely narrow FWHM of 34 nm are realized for 7-PhQAD. These superior results reveal that apart from nitrogen and boron-aromatic systems, QAD framework can also act as a TADF matrix with effective resonance effect, and QAD derivatives are ideal candidates to develop TADF emitters with narrow FWHMs for practical applications.

Original languageEnglish
Pages (from-to)13472-13480
Number of pages9
JournalACS Applied Materials and Interfaces
Volume11
Issue number14
DOIs
Publication statusPublished - Apr 10 2019

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)

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