van der Waals epitaxy for highly tunable all-inorganic transparent flexible ferroelectric luminescent films

Ferroelectric luminescent materials with more unique requirements, such as high-speed, low-cost, and low-power, and being light-weight, all-inorganic, transparent, flexible and wearable, are of great demand for future smart device applications. Here, we report the direct fabrication of highly flexible and transparent Eu-doped 0.94Bi 0.5 Na 0.5 TiO 3 -0.06BaTiO 3 epitaxial thin films on mica substrates via van der Waals epitaxy. The photoluminescence switching of the films exhibits no noticeable decay after being flexed in or out to 2 mm radius for 10 4 cycles, revealing the robust functionality against mechanical bending. Furthermore, we demonstrate that the photoluminescence intensity can be greatly enhanced by the bending-induced mechanical strain either in the tensile or compressive state, with a striking giant gauge factor of 3580. This work illustrates the role of MICAtronics, i.e. , van der Waals epitaxy on mica, in designing all-inorganic flexible ferroelectric luminescent thin films with highly controllable optical properties for application in tunable transparent wearable memory devices, sensors and displays. The direct fabrication of flexible transparent ferroelectric luminescent films on mica with highly tunable photoluminescence response is demonstrated.