Study On High Aspect-ratio Copper Nanowires Based Conductive Electrode Of Triboelectric Nanogenerator

Triboelectric Nanogenerator(TENG),based on nanomaterial preparation,is an energy conversion device.TENGs obtain ubiquitous mechanical energy from the human body and the surrounding environment,including green,sustainable energy such as kinetic energy,water waves,wind energy,and convert it i nto electrical energy which is supply for mobile electronic devices.It has been an explosive growth in research on TENG in the past few years.Although the output performance of TENG is high,the transparency and flexibility are not ideal.Therefore,high output,high transparency flexible TENG are the main research direction currently.Flexible transparent conductive electrode is an important guarantee for achieving high transmittance,high output performance and good mechanical properties of TENG as conductive electrode is a key component of TENG.Electrodes based on copper nanowires(Cu NWs)with high aspect ratio have superior optical,electrical and mechanical properties.A flexible transparent electrode based on Cu NWs is prepared by combining PDMS,which is finally used to prepare flexible and transparent TENG with superior performance.In this paper,the reaction was carried out at 120°C for 4 hours by hydrothermal reduction to obtain curved Cu NWs with a diameter of 37 nm and a length of about 82 ?m.The aspect ratio was as high as 2300.The experiment used a single variable rule to determine the effects of ratio of water and glycerol,volume of oleylamine,ratio of oleylamine and oleic acid,concentrations of glucose,time and temperature on the morphology of Cu NWs.Water and glycerol cosolvents increase the solubility of copper amine complexes and are key factors in the synthesis of ultralong Cu NWs.Ole yamine and oleic acid act as surfactants on the(100)plane,which contributes to the one-dimensional structure of Cu NWs.By adjusting the ratio of oleylamine and olei c acid,the agglomeration of Cu NWs can be effectively suppressed.An appropri ate amount of reducing agent ensure that Cu2+ is reduced sufficiently.Time and temperature are important factors to ensure that Cu NWs react completely.Cu NWs/PDMS electrodes and Cu NWs/PDMS embedded electrodes were prepared.Both embedded and non-embedded electrode have high transmittance and conductivity.The non-embedded electrode has a transmittance of 89.96% when the sheet resistance is 64.31 ?sq-1,and the transmittance of the embedded electrode is 87.74% when the sheet resistance is 71.24 ?sq-1.For the latter,the conductivity is decreased slightly since most of the Cu NWs are buried in the PDMS.However,the antioxidance are significantly improved.The sheet resistance was 0.3 time of the old after the embedded electrode was exposed to the air for one month.However it is almost non-conductive for non-embedded electrode after being exposed to the air for 10 days.The sheet resistance of embedded electrode becomes 1.3 times compare to the original one after bending 1000 times.The sheet resistance is less than doubled when being stretched 50% of the length.A single-electrode triboelectric nanogenerator(SE-TENG)was designed based on the prepared Cu NWs/PDMS embedded electrode.The voltage was as high as 45 V with an electrode area of 2 cm×2 cm.Fix it on the surface of the mouse and we get a 6 V voltage via clicking on the mouse.Connect the device which is the only power supply to a closed circuit in series,about 50 LEDs can be illuminated simultaneously via rubbing the SE-TENG.In addition,we obtain voltage curves with three different peaks via different preasure on the device.PDMS and Cu NWs were directly mixed and PDMS@Cu NWs film was prepared via spin-coating inspired which is equivalent to doping the conductive material Cu NWs in PDMS.The internal structure of the composite film is equ al to an infinite number of parallel plate capacitors.Sandwich-structured TENGs with film being wrapped by two metal electrodes are formed.The capacitance which determines charge density is changed by changing the film thickness,so that the amount of Cu NWs can be incorporated.Ultimately,the output of voltage increase effectively.The film with 180 nm thickness had an open-circuit voltage of 100 V.The performance was the best when adding 0.006 g Cu NWs,and the open-circuit voltage was up to 100 V.