Hybrid‐Piezoelectret Based Highly Efficient Ultrasonic Energy Harvester for Implantable Electronics

Abstract

Implantable ultrasonic energy harvesters that scavenge wireless mechanic energy from ultrasound own remarkable potential in advanced medical protocols for neuroprosthetics, wireless power, biosensor, etc. The main challenge for this kind of device is to achieve high‐efficiency energy conversion in a weak ultrasonic pressure field. Here, a multilayered piezoelectret with strain enhanced piezoelectricity by introducing a parallel‐connected air hole array in an interdielectric layer sandwiched between a pair of electrets for an efficient ultrasonic energy harvester is presented. This device delivers a remarkable peak output power around 13.13 mW and short‐circuits current around 2.2 mA when implanted into tissues at 5~10 mm under an ultrasonic probe setup at 25 mW cm−2, which is higher than the required power threshold of bioelectronic devices and current threshold of nerve stimulation. Furthermore, the feasibility of supplying power to implantable bioelectronics and working as neuroproteins for peripheral nerve stimulation are both demonstrated. It is anticipated that this highly efficient, easily fabricated, and biocompatible device will potentially enable applications for multifunctional and advanced implantable bioelectronics in the next generation of diagnosis and therapy.

Forward polarization enhanced all-polymer based sustainable triboelectric nanogenerator from oriented electrospinning PVDF/cellulose nanofibers for energy harvesting

“…It can be calculated by P ave. = W / t = 0.5 × C × U ( t ) 2 / t and the average power density = P ave. / S , where W is the electric energy stored in a capacitor, U ( t ) is the voltage of the capacitor at t time, C is the capacitance value and t is the charging time. 34 According to the charge curves displayed in Fig. 3e, the P ave. and the average power density were calculated to be 0.841 μW and 0.934 mW m −2 at 3 Hz.…”

Wirelessly Powered Electrical-Stimulation Based on Biodegradable 3D Piezoelectric Scaffolds Promotes the Spinal Cord Injury Repair

“…In this situation, we speculate that remote mechanical activation by ultrasound (US), which has been widely used in clinics and has the advantage of deep tissue penetration, would be a safe and effective approach to induce in vivo piezoelectric stimulation. In addition, the in situ piezoelectric stimulation induced by US irradiation can be performed in a more controllable manner, since we recently demonstrated that the electrical output of a US-responsive transducer can be well programmed with adjustable pulse parameters. − Therefore, the combining of biodegradable piezoelectric scaffolds with programmable US irradiation, which can offer excellent control over the timeline, duration, and strength of in vivo ES, would show potential application for nerve tissue engineering. It should be noted that there is an FDA safety limitation for biomedical US, and the US power transmitted into human tissue should be as low as possible .…”

Stretchable π-conjugated polymer electrets for mechanoelectric generators

“…Second, MEGs do not require an electrolyte and possess high impedance and thus are thought to be safe for human-adaptive power supplies. In recent years, with improvements in the performance of MEGs [2,3] along with the miniaturization and power savings of electronic devices, various practical applications for MEGs, such as wearable devices [4][5][6], sensors [7,8], and transmitters [9], have emerged.…”