Ultrapure Blue Phosphorescent Organic Light-Emitting Diodes Employing a Twisted Pt(II) Complex

• Published in: ACS applied materials & interfaces 2021-11, Vol.13 (44), p.52833-52839
• Main Authors: Chen, Yumeng, Qian, Chunyue, Qin, Ke, Li, Hongbo, Shi, Xiaobo, Lu, Zhenzhong, Ma, Huili, Qin, Tianshi, Hang, Xiao-Chun, Huang, Wei
• Format: Article
• Language: English
• Subjects: Organic Electronic Devices
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.1c13843

Described herein is a stable complex, Pt­(mpzpyOczpy-mesi), embodying efficient, narrow blue emission. The highly twisted structure of the complex improves the stability and efficiency of photo- and electroluminescence by reducing the intermolecular interactions. The complex in solution shows high photoluminescence efficiency (>95%) and radiative decay rate (K r = 2.9 × 105 s–1) with a narrow emission spectrum. The bottom-emitting phosphorescent device, BE1, exhibits durable deep blue emission with CIE coordinates of (0.145, 0.166) and 5.2 h of LT50 at an initial luminance of 685 cd/m2. Top-emitting devices, TE1 and TE2, achieve ultrapure blue color with CIE x,y values of (0.141, 0.068) and (0.140, 0.071), respectively. TE4 shows high brightness of 3405 cd m–2 at 50 mA m–2, EQE of 10.2% at 1000 cd/m2, and almost negligible color deviation around (0.135, 0.096) at viewing angles of 0°–60°.