Wave-Shaped Piezoelectric Nanofiber Membrane Nanogenerator for Acoustic Detection and Recognition

With the rapid development of internet of things and wearable electronics, how to conveniently power uncountable sensors remains a huge challenge. Energy harvesting strategy is suggested to collect and convert environmental energies into electrical energy. Thereinto, piezoelectric polymers are utilized as flexible harvesters to convert mechanical energy. The latter widely distributes in both our daily life and industrial environment. Intrinsic piezoelectric property further drives piezoelectric polymers to construct flexible self-powered strain sensors. However, relatively low piezoelectric performance restricts their application in detection and conversion of weak mechanical excitations. Herein, wave-shaped 3D piezoelectric device was fabricated by embossing electrospun polyvinylidene fluoride nanofibers. This 3D structured device presents better longitudinal and transverse piezoelectric performance than usual flat-type one. This wave-shaped piezoelectric device was developed for acoustic detection and recognition with a frequency resolution better than 0.1 Hz. This wave-shaped device was capable of frequency spectrum analyses of various sound sources from human and animals and well presents its potential for future wearable acoustic sensors and transducers.