Mechanically controlled reversible photoluminescence response in all-inorganic flexible transparent ferroelectric/mica heterostructures

Abstract The ability to reversibly control the luminescent properties of functional materials with diverse external stimuli, such as an electric field, strain, and temperature, is crucial for designing high-performance optical devices. Here, we demonstrate that a purely mechanical strain in a flexible mica substrate triggered by bending can be used to dramatically modify the photoluminescence response of a Pr-doped Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃epitaxial thin film in a stable and repeatable manner with a large gauge factor of up to 6853. The strong dependence of the photoluminescence performance on the mechanical bending arises from strain-induced variations in the lattice symmetry of the host film and the local crystal field around the Pr³⁺. In particular, because of the nature of mica, the film structure exhibits excellent antifatigue characteristics after 10⁴bending cycles as well as high optical transparency in the range of 450–780 nm. This study provides a viable route for exploring the correlation between structural symmetry and photoluminescence in ferroelectric thin-film systems and offers new possibilities for developing all-inorganic, reconfigurable, transparent and flexible light sources, photodetectors, and wearable sensors.