Li Bowen, Gong Yanbin, Wang Lu, Lin Hang, Li Qianqian, Guo Fengyun, Li Zhen, Peng Qian, Shuai Zhigang, Zhao Liancheng, Zhang Yong
School of Materials Science and Engineering , Harbin Institute of Technology , Harbin 150001 , China.
Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials , Wuhan University , Wuhan 430072 , China.
J Phys Chem Lett. 2019 Nov 21;10(22):7141-7147. doi: 10.1021/acs.jpclett.9b02885. Epub 2019 Nov 7.
Achieving efficient ultralong purely organic phosphorescent luminophores is still a big challenge due to the slow intersystem crossing (ISC) process. Herein, we present a facile molecular design strategy that incorporates a secondary group (Br atom or methoxy group) into -BrCz that can significantly enhance the ISC rate constant () and achieve high phosphorescence quantum yields (Φ). As a result, DBrCz and MeBrCz achieved a profound increase of ≈ 10 s and obtained excellent Φ values up to 24.53 and 27.81% in solid powder, respectively. Given the highly efficient Φ and proper τ, DBrCz and MeBrCz are applied to alternating current (AC) light-emitting diodes (LEDs), achieving a white LED with CIE coordinates (0.28, 0.29) and a CRI over 90. As a proof of concept, we demonstrate its compensation effect on the dark duration of AC-LED with a reduced percent flicker of 78%. This result extends a new potential application for RTP luminophores in the lighting field.
由于缓慢的系间窜越（ISC）过程，实现高效的超长纯有机磷光发光体仍然是一个巨大的挑战。在此，我们提出了一种简便的分子设计策略，即将一个二级基团（溴原子或甲氧基）引入到-BrCz中，这可以显著提高ISC速率常数（）并实现高磷光量子产率（Φ）。结果，DBrCz和MeBrCz的 分别大幅增加了约10 s，并且在固体粉末中分别获得了高达24.53%和27.81%的优异Φ值。鉴于高效的Φ和合适的τ，DBrCz和MeBrCz被应用于交流（AC）发光二极管（LED），实现了CIE坐标为（0.28, 0.29）且显色指数超过90的白色LED。作为概念验证，我们展示了其对AC-LED暗持续时间的补偿效果，闪烁百分比降低了78%。这一结果为室温磷光发光体在照明领域拓展了新的潜在应用。
