Stable deep blue organic light emitting diodes with CIE of y < 0.10 based on quinazoline and carbazole units

Publication date: Available online 18 June 2019Source: Chinese Chemical LettersAuthor(s): Bowen Li, Xiang’an Song, Xi Jiang, Zhiyi Li, Fengyun Guo, Ying Wang, Liancheng Zhao, Yong ZhangAbstractAchieving stable deep blue organic light emitting diodes (OLED) with narrow full width at half maximum (FWHM) and color gamut in the range of the commission International de L’Eclairage (CIE) of y ≤ 0.10 is still challenging in display and lighting application. In this investigation, three donor-acceptor (D-A) deep-blue emitters were designed and synthesized via integrating asymmetric quinazoline (PQ) acceptor with weak donating carbazole (Cz) donor. The effect of the position and number of Cz group in PQ unit are investigated, which is also first examples for systematic research about the effect of different position of asymmetric PQ as acceptor on deep OLED. Their bandgaps of 3.12˜3.19 eV and the singlet state energy levels of 3.12˜3.19 eV were found to be sufficiently large to achieve deep blue light. As expected, these emitters-based OLED devices exhibit deep blue emission with the maximum wavelength ≤ 450 nm and narrow FWHM ≈ 60 nm. Especially, a CIE of y = 0.080 was achieved for 4PQ-Cz- based OLED. Significantly, the deep blue electroluminescence (EL) spectra of these three emitters-based OLED devices are very stable and the corresponding CIE coordinates deviation (ΔCIE (x, y)) can be negligible under the applied voltage ranging from 5 V to 9 V.Graphic...
Source: Chinese Chemical Letters - Category: Chemistry Source Type: research