Radical-enhanced photo-activated ultralong organic phosphorescence.

Stimuli-responsive ultralong room temperature phosphorescence materials have attracted great attention due to their great potential in a wide variety of advanced applications. Photo-activated phosphorescence lifetime and photo-activation time are constant and highly dependent on the inherent properties of the materials. It is a great challenge to manipulate them. Herein, we propose a facile strategy to prolong photo-activated phosphorescence emission and shorten photo-activation time by consuming the oxygen in polymer matrix through UV irradiation and radical coupling. The phosphorescence lifetime increases from 0.08 ms to 360 ms after 30-minute UV irradiation. When the guest molecules in solution are photoactivated and subsequently doped into the polymer, the photoactivated phosphorescence lifetime can reach up to 621 ms after just 5-second UV irradiation. This enhancement is attributed to the ability of triarylphosphine radical cations to capture oxygen in polymer through radical coupling. Furthermore, these polymer films have been successfully applied in information storage, programmable afterglow tags, and anti-counterfeiting. This work overcomes the intrinsic limitations of materials and paves the way for regulating photoactivated phosphorescence lifetime and photoactivation time.