Luminescence Color Tuning from Blue to Near Infrared of Stable Luminescent Solid Materials Based on Bis-o-Carborane-Substituted Oligoacenes

4 years ago

Luminescence Color Tuning from Blue to Near Infrared of Stable Luminescent Solid Materials Based on Bis-o-Carborane-Substituted Oligoacenes

Kazuo Tanaka, Kenta Nishino, Yasuhiro Morisaki, Hirofumi Naito, Yoshiki Chujo

Aryl-substituted o-carboranes have shown highly efficient solid-state emission in previous studies. To demonstrate color tuning of the solid-state emission in an aryl-o-carborane-based system, bis-o-carborane-substituted oligoacenes were synthesized and their properties were systematically investigated. Optical and electrochemical measurements revealed efficient decreases in energy band gaps and lowest unoccupied molecular orbital (LUMO) levels by adding a number of fused benzene rings for the extension of π-conjugation. As a consequence, bright solid-state emission was observed in the region from blue to near infrared (NIR). Furthermore, various useful features were obtained from the modified o-carboranes as an optical material. The naphthalene derivatives exhibited aggregation-induced emission (AIE) and almost 100 % quantum efficiency in the crystalline state. Furthermore, it was shown that the tetracene derivative with NIR-emissive properties had high durability toward photo-bleaching under UV irradiation. A series of bis-o-carborane-substituted oligoacene triads from benzene to tetracene were synthesized. All triads showed crystallization-induced emission enhancement, and bright solid-state luminescence from blue to near infrared regions was observed. Furthermore, the tetracene-containing triad showed high durability toward photodegradation.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/asia.201700815