Imperceptible energy harvesting device and biomedical sensor based on ultraflexible ferroelectric transducers and organic diodes

Abstract

Energy autonomy and conformability are essential elements in the next generation of wearable and flexible electronics for healthcare, robotics and cyber-physical systems. This study presents ferroelectric polymer transducers and organic diodes for imperceptible sensing and energy harvesting systems, which are integrated on ultrathin (1-µm) substrates, thus imparting them with excellent flexibility. Simulations show that the sensitivity of ultraflexible ferroelectric polymer transducers is strongly enhanced by using an ultrathin substrate, which allows the mounting on 3D-shaped objects and the stacking in multiple layers. Indeed, ultraflexible ferroelectric polymer transducers have improved sensitivity to strain and pressure, fast response and excellent mechanical stability, thus forming imperceptible wireless e-health patches for precise pulse and blood pressure monitoring. For harvesting biomechanical energy, the transducers are combined with rectifiers based on ultraflexible organic diodes thus comprising an imperceptible, 2.5-µm thin, energy harvesting device with an excellent peak power density of 3 mW·cm−3.

Analysis and design of diode physical limit bandwidth efficient rectification circuit for maximum flat efficiency, wide impedance, and efficiency bandwidths

“…In the wireless power transfer (WPT) and wireless energy harvesting (EH) applications, rectifier always has been an important unit where radio frequency (RF) power must be converted to the direct current (dc) power for powering low power devices like wireless sensor networks, pacemakers, biomedical implants, etc 1 – 6 . A rectifier with high efficiency is crucial in these fields because the RF-dc conversion efficiency of rectification circuits determines such a system’s overall efficiency.…”

Piezoelectric Dynamics of Arterial Pulse for Wearable Continuous Blood Pressure Monitoring

“…Generally, the typical arterial-pulse piezoelectric-response waveform (Figure 1C) should include three gradually weakening peaks, [8,[29][30][31] which is similar to the pattern of changes over time in blood pressure. However, common arterial-pulse piezoelectric-response waveform often include a strong reverse peak followed the first positive peak point [22,23,28,[32][33][34][35] (Figure 1D).…”

“…B) Illustration of piezoelectric dynamic response to arterial pulse from the arterial vessels to the skin. C) Typical arterial-pulse piezoelectric response waveform (T-APW) [8,[29][30][31] featuring three gradually weakening positive peaks, reflecting arterial-pulse pressure changes over time. D) Common arterial-pulse piezoelectric response waveform (C-APW) [23,24,28,[32][33][34][35] featuring a strong reverse peak followed the first positive peak point.…”

Flexible Electronics and Devices as Human–Machine Interfaces for Medical Robotics

“…In the human body, the skin protects internal tissue from damage [79] while transmitting abundant external information to the brain through various high-density subcutaneous receptors, [80] excreting some metabolites and dissipating heat. In this way, the skin acts as a platform for the sensing of external environment and the embodiment of internal body information simultaneously, such as physical (pressure and stretching), [81,82] chemical (perspiration), [83] and physiological (temperature, respiration, and pulse) [84,85] information.…”