title: The Control of Conjugation Lengths and Steric Hindrance to Modulate Aggregation-Induced Emission with High Electroluminescence Properties and Interesting Optical Properties.
abstract: A series of novel AIE-active (aggregation-induced emission) molecules, named SAF-2-TriPE, SAF-3-TriPE, and SAF-4-TriPE, were designed and synthesized through facile reaction procedures. We found that incorporation of the spiro-acridine-fluorene (SAF) group, which is famous for its excellent hole-transporting ability and rigid structure, at different substitution positions on the phenyl ring affected the conjugation lengths of these compounds. Consequently, we have obtained molecules with different emission colors and properties without sacrificing good EL (electroluminescence) characteristics. Accordingly, a device that was based on compound SAF-2-TriPE displayed superior EL characteristics: it emitted green light with ηc, max =10.5 cd A(-1) and ηext, max =4.22 %, whereas a device that was based on compound SAF-3-TriPE emitted blue-green light with ηc, max =3.9 cd A(-1) and ηext, max = 1.71 %. These compounds also displayed different AIE performances: when the fraction of water in the THF solutions of these compounds was increased, we observed a significant improvement in the ΦF of compounds SAF-2-TriPE and SAF-3-TriPE; in contrast, compound SAF-4-TriPE showed an abnormal phenomenon, in that it emitted a strong fluorescence in both pure THF solution and in the aggregated state without a significant change in ΦF . Overall, this systematic study confirmed a relationship between the regioisomerism of the luminophore structure and its AIE activity and the resulting electroluminescent performance in non-doped devices.
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, P. R. China.
authors.forename: Miao-Miao
authors.initials: MM
authors.lastname: Xue
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, P. R. China.
authors.forename: Yue-Min
authors.initials: YM
authors.lastname: Xie
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, P. R. China.
authors.forename: Lin-Song
authors.initials: LS
authors.lastname: Cui
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, P. R. China.
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Liu
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, P. R. China.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Yuan
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, P. R. China.
authors.forename: Yong-Xi
authors.initials: YX
authors.lastname: Li
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, P. R. China. zqjiang@suda.edu.cn.
authors.forename: Zuo-Quan
authors.initials: ZQ
authors.lastname: Jiang
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, P. R. China. lsliao@suda.edu.cn.
authors.forename: Liang-Sheng
authors.initials: LS
authors.lastname: Liao
keywords: UV/Vis spectroscopy; aggregation; conjugation; luminescence; spiro compounds