| Acoustic energy is an indispensable environmental energy source,which is pollution-free,widely distributed.The harsh noise will not only cause irreversible damage to human ears,but also cause serious mental health problems.Generally,acoustic energy is dissipated into thermal energy,while the low-and mid-frequency sound waves are difficult to absorb due to its relatively long wavelength.Hence,effectively absorb low-frequency acoustic sound waves,and monitor them in real time to prevent excessive noise from producing to the human body injury is essential.This work developed a laminated electrospun nanofibers triboelectric acoustic energy harvester（LEN-TAEH）toward self-powered real-time noise decibel monitoring.Through optimizing the porosity,dielectric property of electrospun nanofibers,laminated structure and the configuration parameters of the LEN-TAEH,a maximum Voc of 124 V and Isc of 23.5μA can be obtained by one individual LEN-TAEH with maximum charging rate of 11.5μC/s,and around 100LEDs can be lighted up simultaneously under resonance frequency of 200 Hz and optimal sound intensity level of 104 d B.Furthermore,by stacking two units to form a two-stack LEN-TAEH can register a Voc of 170 V,power density of 1.28 W/m2 and a sensitivity of 53.6 V/Pa under resonance frequency.In addition,the LEN-TAEH behaved excellent working stability and durability with the working output performances remaining above 90%after 30 days of continuous operation.Finally,the functions of real-time noise decibel monitoring and voice recognition are realized under stimulation of different frequencies and sound intensity level,demonstrating the promising application potential of the LEN-TAEH as noise sensor towards self-powered environmental noise monitoring.This work developed a triboelectric nanogenerator（C-TENG）based on coaxial electrospinning.By doping the ferroelectric material KNN-Ca nanorods and optimizing its concentration to improve the piezoelectric properties of the material,the coaxial electrospinning technology is used to realize the nuclear Shell structure electrospun fibers.The Voc and Jsc of the uniaxial electrospinning triboelectric nanogenerator（S-TENG）are 140 V and 6.7 m A/m2,respectively.At the resonance frequency of 200 Hz and the optimal sound intensity level of 104d B,the coaxial spinning the C-TENG composed of silk fiber film has a Voc of 180 V and a short circuit current density(Jsc)of 8 m A/m2,which are 1.29 times and 1.19 times higher than that of S-TENG,and the power density is 0.86 W/m2,which can simultaneously light up 160 LED lights.In addition,C-TENG can also restore the music spectrum with high precision,while achieving a noise reduction effect of 3-5 d B under different sound intensity levels.Finally,the C-TENG is used as a sensor to realize the speed measurement function of expressway section,which provides a theoretical basis and technical support for the future self-powered intelligent transportation field. |
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