Mechano-tunable circularly polarized luminescence of flexible nanocomposite films

Dynamic and controllable manipulation of circularly polarized luminescence (CPL) is highly desirable for potential applications in chiral photonics and electronics. Attempts to manipulte CPL of flexible films through external force have seldom been reported up to date. Herein, we demonstrate a simple and scalable method to fabricate macroscopic chiral assemblies of Ag nanowires (AgNWs) in poly(vinyl alcohol) (PVA) via stirring. The nanocomposites could be utilized as handedness-selective converters to turn achiral fluorescence (FL) into CPL. The handedness of CPL depends on not only the stirring direction but also the spectral overlapping between AgNWs assemblies and dyes. Importantly, reversible modulation of CPL is possible, owing to the reversible change of the orientation and optical activity of AgNWs assemblies during mechanical stretching and shape recovery processes. Moreover, flexible and programmable CPL patterns can be easily fabricated using the inkjet printing technology. Our method could open up a new avenue for rational designs and applications of smart chiroptical devices.