Thermal annealing promoted room temperature phosphorescence: motion models and internal mechanism.

Thermal annealing has been proven to be an efficient method to optimize the device performance of organic and polymeric opto-electronic materials. However, no detailed information of aggregate structures was obtained for a deeper understanding of what happens during thermal annealing. Herein, through modulation of molecular configurations by tunable linkage positions, and the amplified amplitudes of molecular motions by incorporation of additional methylene units, accurate changes of aggregated structures upon thermal annealing have been achieved, accompanying with the 'turn-on' room temperature phosphorescence (RTP) response by about 4800- and 177-fold increase of lifetimes. The stretching and swing motion models have been proposed, which afforded an efficient way to investigate the science of dynamic aggregation in depth.