Dynamic regulation of photoluminescence based on mechanochromic photonic elastomers

Photonic crystals (PCs) are emerging advanced functional materials with a unique capability of regulating light propagation and have been demonstrated promising in tuning photoluminescence (PL) of fluorophores for sensing and displaying devices. However, it remains highly desired and challenging to develop robust PC platforms for facile dynamic regulation of PL of fluorophores. Herein, we demonstrate dynamic regulation of the PL properties of fluorophores by using photonic elastomers (PEs) with a tunable photonic bandgap (PBG) via a facile stretching process. When being combined with fluorophores (e.g., quantum dots (QDs), Rhodamine B (RhB), and rare earth complexes), shifting of the PBG can realize dynamic regulation of PL properties of fluorophores. We show that during stretching, when the PBG matched well with the PL peak, ~1.8-fold enhancement of PL intensity of QDs on the surface of the PEs and ~40% inhibition of PL intensity of RhB incorporated within the PEs. We further showed that the composite PEs with embedded RhB can be used as a multi-mode anticounterfeiting tape, which exhibited mechanochromic properties in both structural color and PL under natural and UV light. This study presents a new platform for the dynamic regulation of PL and expands the practical application prospect of PCs.