Highly coupled and low frequency vibrational energy harvester using lithium niobate on silicon
Giacomo Clementi, Merieme Ouhabaz, Samuel Margueron, Miguel Ángel Suárez, Florent Bassignot, Ludovic Gauthier‐Manuel, Djaffar Belharet, B. Dulmet, Ausrine Bartasyte
Abstract
LiNbO3 has been little studied for the piezoelectric energy harvesting applications. Although it is a cheap piezoelectric material without lead and toxic elements, it beneficiates of technological maturity in single crystal fabrication for optical and acoustic applications. In this Letter, we propose to investigate a (YXlt)/128°/90° LiNbO3 cut as it offers a transverse piezoelectric coupling of k23 = 0.49, which is comparable to that of commonly used PZT ceramics. A flexible beam of 65 mm length and a tip mass made of a LiNbO3 thick film bonded on silicon were studied under 0.1 g sinusoidal acceleration. The beam presented an open-circuit resonance frequency of 105.9 Hz and a displacement up to 1.5 mm. In the frame of a single degree of freedom lumped model with a rectifying bridge, the electromechanical coupling of the device (km2), the figure of merit km2Q, and the normalized average power density were compared to both Pb-based and Pb-free current devices. The generated power density by our device was 965 μW/cm2/g2, which is among the highest reported values compared to both Pb- and Pb-free vibrational harvesting devices.