Regulation of solid-state dual-emission properties by switching luminescence processes based on a bis-o-carborane-modified anthracene triad

Abstract

We herein demonstrate not only the design of combination of luminescence processes in dual-emission properties by selecting preparation protocols but also temperature-driven switching of luminescence processes in dual-emission properties based on a bis-o-carborane-substituted anthracene triad in crystals. We synthesized the triad and obtained crystal polymorphs with or without solvent molecules by changing the type of solvent used for recrystallization. From optical measurements, it was shown that dual-emission properties are composed of different photophysical mechanisms. That is, in the absence of solvent molecules the crystal exhibits dual emission of charge transfer (CT) and excimers, while in their presence the crystal exhibits dual emission of locally excited (LE) and CT emission. Furthermore, intensity ratios between them are sensitive to temperature changes. These luminochromic behaviors are suitable for application in ratiometric sensing systems.