Highly Light-Sensitive Luminescent Cyanostilbene Flexible Dimers
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- 作者：Marta Martí ; nez-Abadí ; a ; Shinto Varghese ; Pilar Romero ; Johannes Gierschner ; Raquel Gimé ; nez and M. Blanca Ros
- 刊名：Advanced Optical Materials
- 出版年：2017
- 出版时间：February 16, 2017
- 年：2017
- 卷：5
- 期：4
- 全文大小：4976K
- ISSN：2195-1071
文摘
Switchable luminescent organic materials with unusual high light-sensitivity in the bulk at room temperature are described. The compounds consist of two promesogenic photoactive cyanostilbene units linked by a flexible spacer with an odd number of carbon atoms, analogous to the structural design of a liquid crystal dimer. Experimental and computational studies support the formation of excimers in solution due to the characteristic geometry of the dimers. In their condensed phases they show a high tendency to pack in lamellar phases, exhibiting bent-core lamellar liquid crystal phases and crystalline polymorphs with different photoluminescence and high quantum yields. The compounds are highly photoreactive, and their photoactivity in terms of photoisomerization and/or photocycloaddition reactions in solution and in the bulk is different. By irradiation of the compounds in the condensed phases at room temperature a fast photochemical process takes place, identified as a photocycloaddition reaction favored by the lamellar packing. Due to this photoreaction a luminescence modulation with green/blue color switching and an increase in quantum yield takes place.