Lead-free (Na0.5,K0.5)NbO3 thin films for the implantable piezoelectric medical sensor applications

The chemical solution-derived lead-free piezoelectric (Na0.5,K0.5)NbO3 (NKN) thin film was successfully prepared for an implantable cardio-mechanical electric sensor (CMES) in pacemakers. The NKN film on the tubular Pt for CMES showed a dense and uniform microstructure with a smooth surface. The maximum dielectric constant of the NKN film was 2000 at a low frequency of 10Hz and the average hydrostatic piezoelectric dh value in an n-dodecan liquid solution was 19.1pC/N at a pulse pressure of 0.025MPa. These results prove that the lead-free NKN film is an attractive candidate for the implantable medical sensor applications. ► Lead-free piezoelectric NKN thin film for CMES applications. ► Single perovskite phase with dense and uniform microstructure. ► Good maximum dielectric constant of 2000 at a low frequency of 10Hz. ► Comparable piezoelectric coefficients (dh) of NKN films to poled bulk ceramics. ► Attractive candidate for the implantable medical sensor applications.