Crystallization-induced emission of 1,2-bis(3-methyl-5-(4-alkylphenyl)-2-thienyl)perfluorocyclopentenes: A mechanical and thermal recording system

• Published in: Dyes and pigments Vol. 160; pp. 450 - 456
• Main Authors: Nakahama, Tatsumoto, Kitagawa, Daichi, Sotome, Hikaru, Ito, Syoji, Miyasaka, Hiroshi, Kobatake, Seiya
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2019
• Subjects: Crystal; Crystallization-induced emission; Diarylethene; Fluorescence recording; Photochromism; Crystallization-induced emission; Fluorescence recording; Diarylethene; Photochromism; Crystal
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2018.08.031

Organic luminescent materials have attracted much attention due to potential application to organic optoelectronics. Search for new molecules with high fluorescence quantum yield in solid states is one of the most important tasks in the research field of the organic luminescent materials. Here, we newly synthesized diarylethenes, 1,2-bis(3-methyl-5-(4-alkylphenyl)-2-thienyl)perfluorocyclopentenes having methyl, ethyl, n-propyl, and n-butyl substituents at the p-position of phenyl rings, and investigated their fluorescence properties in the solid states. The diarylethenes in the crystalline phase exhibited strong fluorescence with relatively high fluorescence quantum yields (Φf) of 0.12–0.20 compared with those in the amorphous phase (Φf = 0.064–0.069), which indicates that the diarylethenes have crystallization-induced emission (CIE) characteristics. The diarylethene having methyl group as the alkyl chain has the highest Φf value among the diarylethenes that we synthesized in this work. We found that the amorphous solid of the diarylethene having methyl group was crystallized after mechanical scratching followed by heating at 90 °C. We successfully demonstrated reversible fluorescence recording based on CIE characteristics and mechanical scratching and heating induced crystallization. [Display omitted] •Diarylethenes having various alkyl chains in the crystalline phase exhibited strong fluorescence compared with those in the amorphous phase.•Fluorescence quantum yields of the crystals decreased with increasing alkyl chain length.•The amorphous solid of the diarylethene having methyl group was crystallized after mechanical scratching followed by heating at 90 °C.•Reversible fluorescence recording based on mechanical scratching and heating induced crystallization was successfully demonstrated.