Preserving high-efficiency luminescence characteristics of an AIE-active fluorophore in thermostable amorphous polymers.

Luminophores usually suffer luminescent quenching when introduced into a polymer backbone or side-chain, which leads to the inefficient luminescence or even no luminescence of the polymer. In this work, alicyclic imide rings were found to be capable of balancing the donor-acceptor properties between the rigid spacer and the AIE-active fluorophore in light-emitting polymers. Along with the non-planar and rigid emitter, the suppressed intramolecular charge-transfer effect and interchain disturbance can efficiently preserve the luminescence characteristics of the active centre resulting in high solid-state photoluminescence quantum yields (PLQYs) of up to 89%. The amorphous polyimides exhibit excellent thermal properties, such as high glass transition temperature (Tg) values (398 oC) and high thermal decomposition temperature (Td) values (538 oC). As far as know, these luminescent polymer materials are of excellent heat resistance with the highest luminescence efficiency reported. The results have significant impact for the precise prediction of the optical properties of light-emitting polymers by appropriate monomer design, providing controllable ways for synthesizing high thermal stability polymeric materials with efficient fluorescence properties.