Wearable lead-free piezoelectric blood pressure sensor based on Li-doped KNN for non-invasive blood pressure monitoring

Abstract

The demand for wearable sensors for non-invasive blood pressure monitoring is increasing as the number of elderly populations increases worldwide. However, conventional cuff-based oscillometric sphygmomanometer has difficulties in continuously monitoring blood pressure. Recently, flexible piezoelectric blood pressure sensors have been reported using piezoelectric PZT and PMN-PT thin films. The flexible piezoelectric blood pressure sensor which is attached to the skin to detect the pulse waveform of the artery, infers the exact blood pressure through Pulse Wave Analysis (PWA) method. However, due to the harmfulness of lead to the human body and the environment, the skin-attachable flexible piezoelectric blood pressure sensor needs improvement so that the lead-containing piezoelectric materials are not used. In this paper, lead-free Li-doped KNN piezoelectric thin film based flexible piezoelectric pressure sensors is reported. In addition, blood pressure analogy based on pulse waveform analysis algorithms are reported using pulse signals measured in carotid arteries. This paper shows the possibility that the flexible piezoelectric pressure sensor based on a lead-free piezoelectric material can replace the previously reported flexible piezoelectric blood pressure sensor based on a lead-containing piezoelectric material.