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Flexible piezoelectric cantilever beam has been realized by depositing lead zirconate titanate (PZT) thin film (4.5 μm) by chemical solution deposition (CSD) onto very thin aluminium foil (16 μm). The tip deflection of the beam has been measured as a function of the frequency of the applied sinusoidal voltage to the PZT film for different amplitudes. Resonance curves have been compared to a classical model of an oscillating system under sinusoidal stress with a very good agreement. Despite of weak ferroelectric properties (remnant polarization: 13 μC/cm²), ultra-large deflection amplitudes have been measured under very moderate applied voltage values: 750 μm@10 V for quasi-static mode and 5 mm@10 V at the resonance frequency (~12 Hz), which makes this PZT/aluminium composite film very promising for highly flexible actuation applications where large displacements are wanted.

The proposed design uses Quantum Dots (QDs) and basic MEMS fabrication techniques to create a flexible thin-film optical heart rate sensor. Fields including health sciences, fitness sciences and psychophysiological studies can benefit from a biosensor that detects heart rate (HR) in a noninvasive manner. Optical heart rate sensors achieve this by being able to collect signals simply through contact with the user. While the sensing method itself is nothing new, the nature of the flexible thin-film structure will allow the device to achieve maintained unobtrusive contact with minimal effort.