An efficient way of harvesting mechanoluminescent light: Flexible pressure sensor application

Mechanoluminescent (ML) materials are used for fabricating sensors and other devices such as artificial skin, colorful displays, and energy harvesting devices. However, a key challenge in developing ML-based sensors is the ability to effectively capture and efficiently transmit ML light from the sensing location. Here we report a flexible and sensitive thin film pressure sensor, created using a novel combination of ML material and perovskite. In this work, we adopted a simple lateral type design of a thin pressure sensor primarily consisting of (i) a sensing layer of copper-doped zinc sulfide (ZnS:Cu)/polydimethylsiloxane (PDMS) composite and (ii) a light absorbing layer of perovskite. The mixed halide perovskite, a light absorbing material, fully absorbs the green light emitted from ZnS:Cu. The sensor demonstrated consistent signal output under the mechanical bending test. A thin encapsulation layer of PMMA on the perovskite layer prevents moisture inclusion. This innovative technique of utilizing integrated thin perovskite to efficiently harvest ML light has the potential to open up new avenues for advanced research in ML-perovskite-based sensor systems.