Research On Flexible Hybrid Nanogenerator And Its Application In Sensors

Nanogenerators have been a hot research topic in the field of micro-nano power generation and sensors in recent years.After years of research,researchers have been able to prepare piezoelectric nanogenerators（PENG）and triboelectric nanogenerators（TENG）based on rigid substrates.Due to the limitations of rigid substrate and single collection mode,people are also studying flexible nanogenerators with high-performance output.In this paper,we successfully prepared a flexible aramid fiber-based triboelectric nanogenerator（AF-TENG）through vacuum filtration and hot pressing.AF-TENG is composed of aramid fibers（AF）and silver nanowires（Ag NWs）.The study found that the electrical output of AF-TENG is positively correlated with the length of AF and the aspect ratio of Ag NWs.Ag NWs with an area fraction of 1.0g/m²and hot pressing at 110°C can optimize the performance of AF-TENG,and its open circuit voltage(V_OC)and short circuit current(I_SC)reach 133.5V and 1.15μA,respectively.When working under a load resistance of15MΩ,the device power density reaches 118.2m W/m².The output of AF-TENG has a linear relationship with the relative humidity of the air.The performance of AF-TENG is stable.After being exposed to the air for 300 days,the performance still remains above 80%of the original.We prepared a zinc oxide-based piezoelectric nanogenerator（ZnO-PENG）by hydrothermal method.Zinc oxide nanorod array（ZnO NRs）is used as piezoelectric layer,flexible and transparent ITO/Kapton film is used as electrode and base material to form ZnO-PENG.The microscopic morphology and structure of ZnO NRs were analyzed by AFM,SEM,XRD,PL and other characterization methods.The study found that ZnO NRs have a high aspect ratio（25.68）,good c-axis orientation and fewer defect states.The piezoelectric output of ZnO-PENG is positively correlated with the device area,and the series connection can improve the output characteristics of the device.ZnO-PENG has a strong ability to perceive dynamic pressure such as different pressure application methods and different bending release speeds.ZnO-PENG shows a good response to ultraviolet light（49.02%）,which is attributed to the enhanced screening effect.We integrate AF-TENG and ZnO-PENG to form a flexible composite nanogenerator（AF-ZnO-HNG）.We analyzed the working process of AF-ZnO-HNG and verified that the piezoelectric unit has lower internal impedance than the triboelectric unit through different connection methods of the power generation unit.After connecting the energy storage circuit,AF-ZnO-HNG can drive digital tubes,50 LEDs or electronic watches.Finally,based on the AF-ZnO-HNG,we implemented a humidity sensor,an ultraviolet sensor and a pedometer sensor system.