High-performance ambipolar responses to oxidizing NO 2 and reducing NH 3 based on the self-assembled film of an amphiphilic tris(phthalocyaninato) europium complex

• Published in: New journal of chemistry 2017, Vol.41 (20), p.11955-11961
• Main Authors: Wang, Haoyuan, Kong, Xia, Zhao, Shuai, Wu, Junshi, Li, Xiyou, Chen, Yanli
• Format: Article
• Language: English
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/C7NJ02790G

A heteroleptic amphiphilic tris(phthalocyaninato) europium triple-decker complex, (Pc)Eu{Pc[(OC 2 H 4 ) 3 OCH 3 ] 8 }Eu{Pc[(OC 2 H 4 ) 3 OCH 3 ] 8 } ( 1 ), has been designed and synthesized successfully. The hydrophilic polyoxyethylene substituents attached onto the periphery of two phthalocyanine rings in the sandwich-type phthalocyaninato triple-decker not only increase the solubility and improve the film-forming ability, but also importantly ensure the suitable HOMO and LUMO energy levels and thus successfully realize amphiphilic ambipolar organic semiconductors. The solution-processed thin film of the complex is prepared by a simple and low-cost quasi-Langmuir–Shäfer (QLS) method. Importantly, within the dynamic exposure period of 30 s, highly sensitive, stable, reproducible n-type response to electron-accepting gas NO 2 in the range of 50–500 ppb and p-type response to electron-donating gas NH 3 in 5–25 ppm range, have been first revealed, based on the QLS film of 1 at room temperature, depending on the optimized molecular packing in J-aggregation mode with a large specific surface area and good film conductivity. Furthermore, the responses of the QLS film are all linearly correlated with either NO 2 or NH 3 with good sensitivity of 0.06% ppb −1 and 0.17% ppm −1 , respectively, indicating the great potential of phthalocyanine-based rare earth triple-decker complexes in the field of chemical sensors. The present result provides a new strategy to obtain high-performance room-temperature gas sensors by the molecular design combined with a low-cost solution-based method.