Zhou Fan, Pan Yi, Hung Wen-Yi, Chen Ching-Feng, Chen Kui-Ming, Li Jian-Liang, Yiu Shek-Man, Liu Yi-Mei, Chou Pi-Tai, Chi Yun, Lau Kai-Chung
Department of Materials Science and Engineering, Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Kowloon, 999077, Hong Kong SAR.
Department of Chemistry, City University of Hong Kong, Kowloon, 999077, Hong Kong SAR.
Chemistry. 2024 Oct 17;30(58):e202402636. doi: 10.1002/chem.202402636. Epub 2024 Oct 2.
In this work, we report the syntheses of three Pt(II) emitters, namely, Pt4N1, Pt4N2, and Pt4N3, to which their tetradentate chelates were assembled by linking two pyrazolate chelates with a single xylenylamino entity. Functionalization of Pt4N1 was achieved upon the addition of electronegative CF substituent on pyridinyl groups and switching to more electron-deficient pyrazinyl groups in giving Pt4N2 and Pt4N3, respectively. The vertically arranged xylenylamino entity has effectively suppressed the inter-molecular π-π stacking and Pt⋅⋅⋅Pt interaction, as shown by the single crystal X-ray structural analyses. Upon fabrication of OLED devices, Pt4N2 and Pt4N3 based devices delivered efficient cyan and green emission, with an EQE of 15.2 % and 11.2 %, respectively, affirming the successfulness of the tetradentate chelating strategy.