Tetraphenylcyclopentadiene Derivatives: Aggregation-Induced Emission, Adjustable Luminescence from Green to Blue, Efficient Undoped OLED Performance and Good Mechanochromic Properties.
Silole derivatives, the first reported and famous AIEgens, are a series of Si-containing conjugated rings with the σ*-π* conjugation, and this unique electronic structure imparts them high electron affinity and fast electron mobility, but not ideal blue luminogens due to their relatively long conjugation length. By replacing the Si atom with the C one, six new AIEgens without the σ*-π* conjugation effect are successfully synthesized based on a tetraphenylcyclopentadiene core. In addition to the sky-blue emission (λEL= 492 nm) with Lmax, ηC,max, and ηP,maxup to 24 096 cd m-2, 6.80 cd A-1, and 4.07 lm W-1, respectively, the careful control of the conjugation degree by changing the linkage mode, results in the blue one (λEL= 440 nm) with relatively good performance (Lmax: 8721 cd m-2and ηC,max: 3.40 cd A-1), indicating that the replacement of the Si atom by C one is an alternative design strategy to yield blue even deep-blue AIEgens with good device performance. Meanwhile, their reversible mechanochromic properties are realized with apparent fluorescence changes between deep-blue and green emissive colors, offering them additional promising applications in optoelectronic devices.
Department of Chemistry, Wuhan University, Wuhan, 430072, China.
Zhijun
Z
Ruan
Key Laboratory for Organic Electronics and Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, Nanjing, 210023, P. R. China.
Le
L
Li
College of Chemistry and Chemical Engineering, Hubei University, Wuhan, 430062, China.
Can
C
Wang
Department of Chemistry, Wuhan University, Wuhan, 430072, China.
Yujun
Y
Xie
College of Chemistry and Chemical Engineering, Hubei University, Wuhan, 430062, China.
Quanyuan
Q
Hu
Key Laboratory of Organic Solids, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Qian
Q
Peng
Key Laboratory for Organic Electronics and Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, Nanjing, 210023, P. R. China.
Shanghui
S
Ye
Department of Chemistry, Wuhan University, Wuhan, 430072, China.
Qianqian
Q
Li
Department of Chemistry, Wuhan University, Wuhan, 430072, China.
Zhen
Z
Li
aggregation-induced emission; blue emitters; mechanochromism; organic light-emitting diodes