A high-voltage transparent triboelectric nanogenerator

Abstract

A high voltage transparent triboelectric nanogenerator (TENG) comprising a) a lower substrate, said lower substrate b) an upper substrate, said upper substrate c) four stainless steel springs located at the corners of lower substrate. A tremendous improvement in the output performance of flexible-transparent triboelectric nanogenerator from 280 Vpp to > 3 kVpp and 2 µApp to > 35 µApp with an instantaneous peak power density of > 20 W / m2 is achieved after incorporating the enhancement techniques. Further, the device was redesigned to a spring assisted rigid form and scaled up to 16 cm2 which generates an output voltage of > 4 kVpp, and a short circuit current of > 45 µApp, under an applied force of 20 N. Furthermore, the spring assisted rigid triboelectric nanogenerator is integrated with a footwear, enabling the scavenging of biomechanical energy, opening up exciting possibilities for self-powered wearable electronics and for powering sensor networks.

Description

[0001] PT / 2026 / 11087

[0002] A HIGH-VOLTAGE TRANSPARENT TRIBOELECTRIC NANOGENERATOR

[0003] FIELD OF THE INVENTION

[0004] The present invention relates generators and more specifically, to the development of high voltage transparent triboelectric nanogenerator fabricated by combining the effect of two simple, cost effective and scalable techniques such as intermediate layer embedding and dielectric tuning to improve the triboelectric charge density and hence the output performance of triboelectric nanogenerator.

[0005] BACKGROUND OF THE INVENTION

[0006] The age of Internet of Things (loT) creates a great demand for sustainable power sources that do not need to be replaced or recharged. Batteries that require replacement or recharging at frequent intervals, and which are prone to explosion and causing other safety risks, can be substituted with triboelectric nanogenerators that efficiently transform mechanical energy into electrical energy. Due to its low-frequency mechanical energy harvesting and self-powering nature, triboelectric nanogenerator receives greater attention for loT applications over conventional electromagnetic generators. Simple structure, high output performance, ease of fabrication, and universal availability of materials are other important characteristics of triboelectric nanogenerator.

[0007] The triboelectric nanogenerator is a unique technology among renewable energy harvesting mechanisms in which it can harvest mechanical energy from polymers. In order to attain high output performance, polymers have been chosen as triboelectric materials, owing to their excellent ability to capture and transfer charges during contact electrification. In recent decades, polymer materials have been developed and implemented at a rapid pace in the field of energy as a result of advances in the conversion of renewable energy into electricity. The output performance of the triboelectric nanogenerator can be improved using some techniques such as surface modifications, structural modifications, and chemical modifications, etc.

[0008] The enhanced triboelectric charge generation on the surface of the contactingPT / 2026 / 11087

[0009] materials can be achieved by increasing effective contact area by surface modifications or modifying the chemical parameters of the surface by adjusting functional groups with different electron accepting and donating capabilities. In addition to contact area, functional group grafting, and structural factors, the capacity of the material to retain charge also affects the triboelectric charge density.

[0010] So, here the

[0011]

[0012] invention introduce effective

[0013]

[0014] to enhance the triboelectric

[0015]

[0016] the combined effect of intermediate

[0017]

[0018] dielectric ceramic particles and hence the

[0019]

[0020] of triboelectric

[0021]

[0022] The prior arts disclose a number of triboelectric nanogenerators; however, these are constrained by limited efficiency for high output generation and involve intricate fabrication procedures. No prior arts that involve the use of enhancement with the combined effect of intermediate layer embedding and dielectric tuning have been found.

[0023] The closest prior art may be an Indian patent IN201811022094 A, 2019, relates to the fabrication of a flexible nanocomposite film by incorporating piezoelectric / ferroelectric nanostructures (such as ZnO, BaTiO3, and NaNbOa) into ferroelectric polymers (PVDF) as one friction layer and PTFE as another friction layer for enhanced triboelectric performance. The output performance of triboelectric nanogenerator improved from 1 pA to 1.6 pA and from 98 V to 119 V after the incorporation of ZnO nanoparticles into the PVDF.

[0024] Another patent application, CN115724460 A, 2023, describes the fabrication of a perovskite material-based friction nanogenerator, which comprises gold nichrome foil as positive friction layer and electrospun PVDF-HFP composite nanofibers incorporating MXene nanoparticles, platinum nanowires (PtNWs) and perovskite nanoparticles as negative friction layer. A higher dielectric constant is achieved by mixing perovskite nanoparticles with PVDF-HFP, which results in a material with better surface charge density and a greater capacity to store triboelectric charges.

[0025] In another patent application CN115262088 A, 2022, discloses thePT / 2026 / 11087

[0026] piezoelectric / triboelectric output performance enhancement by improving the electroactive phase in PVDF achieved by preparing a PVDF / PANI-ZnS composite film via electrospinning technique. A 9 cm2PENG is fabricated for piezoelectric performance testing, which generates an open circuit voltage of 60 V and a short circuit current of 1.8 pA. An output voltage of 1300 V and a short circuit current density of 45 pA is obtained from the triboelectric performance testing using a composite film with a larger area of 30 cm2.

[0027] In another close prior art, referred as China patent, CN114221572 A, 2022, discloses a piezoelectric-triboelectricity composite sensor based on a flexible porous PVDF-BTO composite membrane prepared using electrostatic spinning technique, which is used as the negative friction material and natural rubber membrane is used as a positive friction material. The device is fabricated with a contact area of 2.5 x 2.5 cm2, generating an improved open circuit voltage of 124 V and a short circuit current of 7.2 pA with a power density of 0.39 W / m2.

[0028] Reference may also be made to the US patent WO2021225677 A1 , 2021, describes the triboelectric nanogenerator with one friction layer as PVA-based biocompatible polymer and the counter friction layer comprises of polyimide, PTFE, PDMS, PVC, PP, or a metal, which generates an open circuit voltage of 5.9 V and a short circuit current of 29.2 nA.

[0029] Another patent application, KR20220119871 A, 2022, describes a method of designing a dual purposes smart home applicable triboelectric nanogenerator using plastic and electronic wastes. The nanogenerator has two functions such as it can sense motion for theft prevention and can directly providing harvested mechanical energy to power portable electronic devices, utilizing friction between positive and negative friction layers. Using cotton and PTFE as positive and negative material respectively, the triboelectric nanogenerator generates an output voltage of 350 V and a short circuit current of 16 pA.

[0030] Another patent application CN110649835B B, 2020, presents an all-inorganic CsPbBr3 perovskite and PVDF based friction nanogenerator prepared on FTO or ITO conductive glass with improved electrical output performance and power densityPT / 2026 / 11087

[0031] through optimized components and surface properties. An open circuit voltage of 250 V and a short circuit current density of 37 mA / m2is obtained with a peak power density of 2.5 W / m2.

[0032] The patent application CN110417293B B, 2022, introduces an organic ferroelectric nanofiber reinforced friction nano-generator with improved electrical output performance through the addition of organic ferroelectric nanofiber layers of Nylon 11 and PVDF. An output voltage of 800 V and a short circuit current of 29 pA is obtained under a higher applied force of 100 N at a frequency of 2 Hz.

[0033] Another patent application, KR102217033 B1, 2021, describes a textile-based triboelectric nanogenerator, with MWCNT / Nylon as the first material and Nanoarchitecture polydimethylsiloxane (NA-PDMS) as the second material. The device with a contact area of 4 cm2generates an output voltage of 400V and a short circuit current of 22 pA.

[0034] However none of the above prior art discuss such high voltage transparent triboelectric nanogenerator (TENG) comprising a) a lower substrate, said lower substrate b) an upper substrate, said upper substrate c) four stainless steel springs located at the corners of lower substrate. A tremendous improvement in the output performance of flexible-transparent triboelectric nanogenerator from 280 Vppto > 3 kVppand 2 Appto > 35 Appwith an instantaneous peak power density of > 20 W / m2is achieved after incorporating the enhancement techniques.

[0035] OBJECTIVES OF THE INVENTION

[0036] Against this background, the following are the objectives of the present invention; The main objective of the present invention is to develop a high voltage transparent triboelectric nanogenerator that combines effect of intermediate layer embedding and dielectric tuning to achieve enhanced output performance.

[0037] Another objective is the present invention is to optimize of material properties which involves the spin coating parameters and curing conditions.PT / 2026 / 11087

[0038] Another objective of the present invention is to investigate the influence of different dielectric ceramic filler concentrations on the output performance of flexible triboelectric nanogenerators with one material bare and the other composite film.

[0039] Another objective of the present invention is to analyze the stability and reliability of the triboelectric nanogenerator under continuous testing cycles of mechanical operation.

[0040] Another objective of the present invention is to scale up the triboelectric nanogenerator to larger area device supported by a spring assisted rigid structure to enable the easy integration of triboelectric nanogenerator with footwears to harvest biomechanical energy from footsteps.

[0041] Another objective of the present invention is to demonstrate the practical applications of the triboelectric nanogenerator by powering small electronic devices such as calculators, thermometers, and LED lights.

[0042] SUMMARY OF INVENTION

[0043] The main aspect of the invention is to provide a high voltage transparent triboelectric nanogenerator (TENG) comprising: a) a lower substrate, said lower substrate including: i) an ITO (indium tin oxide) layer deposited at the lower substrate of mylar sheet and acting as a positive electrode, ii) a PET (polyethylene terephthalate) layer deposited above the ITO layer, iii) a PVDF (polyvinylidene difluoride) layer filled with CCTO (calcium copper titanium oxide) nanoparticle deposited above the PET layer which acts as a negative layer; b) an upper substrate, said upper substrate including: i) an ITO (indium tin oxide) layer deposited at the upper substrate of mylar sheet and acting as a negative electrode, ii) a Nylon 6,6 layer filled with CCTO (calcium copper titanium oxide) nanoparticle deposited on top of the ITO layer which acts as a positive layer; c) four stainless steel springs located at the corners of lower substrate. In contact-separation mode, with either flexible or rigid form factors and triboelectrification between polyvinylidene fluoride (PVDF) and Nylon 6,6 flexible transparent films. The combination of intermediate layer integration and dielectric tuning of contact layers facilitate enhanced energy generation from mechanicalPT / 2026 / 11087

[0044] forces.

[0045] In another aspect of the present in invention, the development of high voltage transparent triboelectric nanogenerator based on Nylon 6,6 and polyvinylidene fluoride (PVDF) films, which’s remarkable electrical output performance is achieved by employing a unique approach of embedding an intermediate layer in TENG device structure and dielectric tuning using high dielectric ceramic filler, CCTO. A better output performance is achieved by incorporating intermediate layer embedding technique, which facilitate improved charge separation and transfer within the triboelectric nanogenerator. Furthermore, with tuning the dielectric properties of triboelectric materials, improved charge storage capacity is achieved, resulting in a more efficient and high-voltage output triboelectric nanogenerator.

[0046] In another aspect of the present in invention, the bare and composite films of Nylon 6,6 and PVDF were prepared on ITO coated PET via facile, inexpensive, and easy scalable spin coating technique. The composite films exhibit enhanced dielectric properties, resulting in an improved ability to generate and store triboelectric charges. The electrical output performance of Nylon 6,6 - PVDF film-based flexible-transparent triboelectric nanogenerator is enhanced from 280 Vppto > 3 kVppand 2 pAppto > 35 pAppin voltage and short-circuit current values respectively, after adopting simple and effective strategies involving the combined effect of dielectric tuning and the intermediate layer embedding. The triboelectric nanogenerator is capable of maintaining consistent power generation over a long period, the film surface also shows no damage over long-term operations. Further, the device was redesigned to a spring assisted rigid form and scaled up to 16 cm2to be integrated with a shoe to harvest the biomechanical energy from footsteps while walking and running, and consequently powering small electronic gadgets and lighting up 60 green LEDs directly. Future smart wearable electronics will benefit from the integration of triboelectric nanogenerators into footwear, as demonstrated by our invention, which captures biomechanical energy lost during day-to-day activities.

[0047] Brief description of the drawings

[0048] These and other features, aspects, and advantages of the present invention whichPT / 2026 / 11087

[0049] will become better understood with reference to the following description, claims and accompanying drawings were

[0050] Figure 1: Photographs of triboelectric nanogenerator (a) flexible-transparent triboelectric nanogenerator, and (b) Spring assisted rigid triboelectric nanogenerator. Schematic representation of triboelectric nanogenerator (c) flexible-transparent triboelectric nanogenerator and (d) Spring assisted rigid triboelectric nanogenerator, as per an embodiment herein.

[0051] Figure 2: Working mechanism of Nylon 6,6 - PVDF triboelectric nanogenerator, (a) Initial state, (b)triboelectric charge generation during contact electrification, (c) electron flow through external circuit during separation, (d) state of maximum separation gap, and (e) backflow of electron during pressing cycle. Working mechanism of Nylon 6,6 - PVDF triboelectric nanogenerator (a) Triboelectric charge generation during contact electrification, (b) electron flow through external circuit during separation, (c) state of maximum separation gap and (d) backflow of electron during pressing cycle, as per an embodiment herein.

[0052] Figure 3: Output signal generated by the bare Nylon 6,6 - PVDF flexible-transparent triboelectric nanogenerator without and with PET interlayer between PVDF film and ITO electrode: (a) Output voltage measured across 1.05 GO, and (b) Short circuit current, as per an embodiment herein.

[0053] Figure 4: The frequency dependent dielectric permittivity of bare and composite films: (a) CCTO / Nylon 6,6 films, and (b) CCTO / PVDF films, as per an embodiment herein.

[0054] Figure 5: Output performance of flexible-transparent triboelectric nanogenerator with different CCTO wt.%: (a) and (b) Output voltage and short circuit current of CCTO / Nylon 6,6 - PVDF flexible-transparent triboelectric nanogenerator, (c) and (d) Output voltage and short circuit current of Nylon 6,6 - CCTO / PVDF flexible-transparent triboelectric nanogenerator, as per an embodiment herein.

[0055] Figure 6: The electrical output of Nylon 6,6 - CCTO / PVDF flexible-transparentPT / 2026 / 11087

[0056] triboelectric nanogenerator as a function of load resistance under a force of ~15 N at 4 Hz: (a) VI graph, and (b) Peak power density, as per an embodiment herein.

[0057] Figure 7: Output performance of Nylon 6,6 - CCTO / PVDF spring assisted rigid triboelectric nanogenerators under an applied force of 20 N at 4 Hz: (a) Output voltage, and (b) Short circuit current. The electrical output as a function of load resistance under a force of 20 N at 4 Hz: (c) VI graph, (c) Capacitor charging curves for 10, 23.5, 47 and 100 pF commercial capacitors, as per an embodiment herein.

[0058] Figure 8: The reliability analysis of Nylon 6,6 - CCTO / PVDF spring assisted rigid triboelectric nanogenerator over 10,000 cycles of operation: (a) Output voltage, and (b) short circuit current, as per an embodiment herein.

[0059] Figure 9: Powering electronic gadgets using spring assisted rigid triboelectric nanogenerator (a) digital calculator, (b) digital thermometer and (c) green LEDs, as per an embodiment herein.

[0060] Figure 10: Biomechanical energy harvesting from human activities such as walking and running: (c) Output voltage, and (d) Short circuit current, as per an embodiment herein.

[0061] DETAILED DESCRIPTION OF THE INVENTION

[0062] In order to facilitate a better understanding of the invention, a detailed description of the preferred embodiments of the present invention will now be explained with reference to the accompanying drawings. It needs to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limiting but merely as the basis for the claims and as a basis for teaching one skilled in the art of how to make or use the invention.

[0063] The present invention provide a high voltage transparent triboelectric nanogenerator (TENG) comprising: a) a lower substrate, said lower substrate including: i) an ITO (indium tin oxide) layer deposited at the lower substrate of mylar sheet and acting asPT / 2026 / 11087

[0064] a positive electrode, ii) a PET (polyethylene terephthalate) layer deposited above the ITO layer, iii) a PVDF (polyvinylidene difluoride) layer filled with CCTO (calcium copper titanium oxide) nanoparticle deposited above the PET layer which acts as a negative layer; b) an upper substrate, said upper substrate including: i) an ITO (indium tin oxide) layer deposited at the upper substrate of mylar sheet and acting as a negative electrode, ii) a Nylon 6,6 layer filled with CCTO (calcium copper titanium oxide) nanoparticle deposited on top of the ITO layer which acts as a positive layer; c) four stainless steel springs located at the corners of lower substrate. In contactseparation mode, with either flexible or rigid form factors and triboelectrification between polyvinylidene fluoride (PVDF) and Nylon 6,6 flexible transparent films. The combination of intermediate layer integration and dielectric tuning of contact layers facilitate enhanced energy generation from mechanical forces.

[0065] Further, the synthesis of high dielectric ceramic filler, calcium copper titanate [CaCu3Ti40i2 (CCTO)] for preparation of ceramic filler-dispersed polymer (PVDF and Nylon 6,6) films with improved dielectric permittivity, and optimize the filler concentration in the polymer films are designed to enhance the output energy generation owing to the improved charge storing capability.

[0066] An optimum percentage of CCTO i.e., 0.75 wt% embedded in PVDF layer generates a peak-to-peak electrical output having a voltage of 4.3 kVppand short circuit current of 45 pAppfor a rigid triboelectric nanogenerator.

[0067] The present invention introduces a significant advance in the field of energy harvesting technologies: the high voltage transparent triboelectric nanogenerator. This cutting-edge technology is made possible by a one-of-a-kind combination of intermediate layer embedding and dielectric tuning. By combining these strategies, the triboelectric nanogenerator achieves a significant improvement in output performance, allowing for improved triboelectric charge generation, separation and transfer within the device. The present investigation also covers the utilization of generated electrical energy from the triboelectric nanogenerator to power small electronic gadgets and harnessing the squandered biomechanical energy from daily human activities.PT / 2026 / 11087

[0068] The present invention as illustrated in Figure 1 provides Flexible-transparent triboelectric nanogenerator and spring assisted rigid triboelectric nanogenerator are fabricated using the as transparent bare and composite films of Nylon 6,6 and PVDF as the tribopositive and tribonegative material respectively, with ITO as electrode and PET as interlayer. The photographs and the 3D schematic representation of the flexible-transparent triboelectric nanogenerator with a contact area of 4 cm2and a separation gap of 5 mm and spring assisted rigid triboelectric nanogenerator with a contact area of 16 cm2and a separation gap of 2 mm designed in CS mode is displayed in Figure 1.

[0069] The present invention as illustrated in Figure 2 provides schematically describes the working principle of contact separation (CS) mode triboelectric nanogenerator with Nylon 6,6 as tribopositive material, PVDF as tribonegative material, ITO as transparent electrode and PET as an interlayer between PVDF and ITO.

[0070] The present invention as illustrated in Figure 2 (b) illustrates the generation of triboelectric charges on the surface of Nylon 6,6 and PVDF film, when they come into contact under vertically applied force. During the releasing state (Figure 2 (c)), induction of opposite charges on the electrodes creates a potential difference, leading to a current flow through the external circuit. Pressing cycle reduces potential difference between the electrodes, leads to the flow of current in opposite direction (Figure 2 (e)). The periodic pressing and releasing cycle of triboelectric nanogenerator drives back and forth current flow across the external circuit, generating the alternating voltage and current signals.

[0071] The present invention as illustrated in Figure 3 (a) and (b) shows the electrical output performance of bare Nylon 6,6 and PVDF film-based flexible-transparent triboelectric nanogenerator without and with PET interlayer between PVDF film and ITO electrode under an input force of ~15 N at a frequency of 4 Hz. The introduction of PET interlayer between the PVDF film and ITO electrode enhanced the output voltage and short circuit current from 280 V to 1490 V and 2 to 12 pA (peak-to-peak), respectively.

[0072] The present invention as illustrated in Figure 4 provides dielectric permittivity of barePT / 2026 / 11087

[0073] and composite films of Nylon 6,6 and PVDF were studied in a frequency range of 100 Hz to 2 MHz. Figure 4 illustrates the frequency-dependent dielectric permittivity of the bare and composite films of Nylon 6,6 and PVDF with CCTO filler wt.% (lower, optimum, and higher). At 1 kHz, the bare Nylon 6,6 film exhibited a dielectric permittivity of 2.4, while the PVDF film had a dielectric value of 7.59. The dielectric permittivity of the Nylon 6,6 and PVDF composite films exhibits a rising trend with increasing CCTO wt.%. At 1 kHz, the Nylon 6,6 and PVDF films showed an improved dielectric permittivity of 4.31 and 9.77, respectively, with the addition of 2 wt.% of CCTO.

[0074] The present invention as illustrated in Figure 5 systematically displays the output voltage and short circuit current of flexible-transparent triboelectric nanogenerator with different CCTO wt.% in Nylon 6,6 and PVDF under ~15 N at 4 Hz. Initially, the output performance of flexible-transparent triboelectric nanogenerator with CCTO / Nylon 6,6 as tribopositive material with bare PVDF as counter material is investigated by varying the dielectric filler wt.% from 0 - 2 wt.%.

[0075] The present invention as illustrated in Figures 5 (a) and (b) show the output voltage and short circuit current generated by bare PVDF and CCTO / Nylon 6,6 composite film-based flexible-transparent triboelectric nanogenerator with 0 - 2 wt. % of CCTO in Nylon 6,6. The output performance of the device is enhanced after adding CCTO into the Nylon 6,6, the output voltage and short circuit current (peak-to-peak) of the device with 1 wt.% CCTO reached 2.6 kV and 33 pA respectively. When the CCTO wt.% is 1.5 and 2 wt.%, the output voltage is reduced to 1 .85 kV, and 1.73 kV, and the short circuit current is lowered to 20 pA, and 13.5 pA, respectively. Similarly, in the case of bare Nylon 6,6 and CCTO / PVDF composite film-based flexible-transparent triboelectric nanogenerator, the output performance shows an increasing trend with CCTO wt.% from 0 - 0.75 wt.% and saturates with an output voltage of 3.17 kV and a short circuit current of 36 pA (Figure 5 (c)and (d)). However, when the wt.% of CCTO further increases from 0.75 wt.% to 2 wt.%, the output voltage and short circuit current decrease to 1.55 kV and 13 pA, respectively.

[0076] The present invention as illustrated in Figure 6 (a) displays the V-l graph that illustrates the variation of output voltage and current against external load resistance.PT / 2026 / 11087

[0077] The peak power density delivered by the Nylon 6,6 - CCTO / PVDF flexible-transparent triboelectric nanogenerator is shown in the Figure 6 (b). After adding 0.75 wt.% CCTO to PVDF film, the power density goes up to 20.25 W / m2, which is a 6.38-fold improvement over the bare flexible-transparent triboelectric nanogenerator (with PET interlayer).

[0078] The present invention as illustrated in Figure 7 (a) and (b) shows the consolidated electrical output performance of spring assisted rigid triboelectric nanogenerators under an input force of 20 N at a frequency of 4 Hz. Nylon 6,6 - CCTO / PVDF spring assisted rigid triboelectric nanogenerator generates an output voltage of 2.6 kV and a short circuit current of 33 pA.

[0079] The present invention as illustrated in Figure 7 (c) shows the variation in V & I characteristics of the Nylon 6,6 - CCTO / PVDF spring assisted rigid triboelectric nanogenerator, tested under an applied force of 20 N at 4 Hz frequency, by varying the load resistance from 1 O to 1.05 GO. The triboelectric nanogenerator is integrated with a bridge rectifier circuit and commercial capacitors to evaluate the capacitor charging profile. The charging of commercial capacitors such as 10, 23.5, 47 and 100 pF using Nylon 6,6 - CCTO / PVDF spring assisted rigid triboelectric nanogenerator is shown in Figure 7 (d).

[0080] The present invention as illustrated in Figure 8 (a) and (b) displays the output voltage and short circuit current produced by the Nylon 6,6 - CCTO / PVDF spring assisted rigid triboelectric nanogenerator over 10,000 cycles of operation. There is no apparent change in device’s output voltage and short circuit current after 10,000 continuous testing cycles of operation with the same input mechanical parameters. These outcomes clearly show the outstanding stability and reliability device for long term practical applications.

[0081] The present invention as illustrated in Figure 9 (a), (b) and (c) portrays the demonstration of the electrical energy generated by the device to power small-scale electronic devices such as digital calculator, thermometer and direct lighting of green LEDs.PT / 2026 / 11087

[0082] The present invention as illustrated in Figure 10 provides an embodiment of the invention which includes Nylon 6,6 - CCTO / PVDF spring assisted rigid triboelectric nanogenerator is integrated with a shoe to demonstrate the practical wearable and portable application of the device, enabling the conversion of biomechanical energy from footsteps into electrical energy. The output voltage and short circuit current signals generated during walking and running are shown in Figure 10 (a) and (b) respectively. These signals demonstrate the efficiency of the triboelectric nanogenerator in converting biomechanical energy into useful electrical output, which would otherwise be squandered during human motion. Here, a person with a weight of 50 kg can generate an electrical output of 900 V and 10 pA while walking, and 1.3 kV and 17 pA while running. This allows the conversion of biomechanical energy lost during walking, jogging, or exercising on a treadmill into to useful electrical energy to instantaneously power or charge electronic gadgets.

[0083] In initial embodiment of the present invention, describes the synthesis of high dielectric ceramic filler, CCTO and the preparation of bare and composite films of PVDF and Nylon 6,6 films. The high dielectric ceramic particle, CCTO is synthesized via ultrasonically aided solid-state method and the bare and composite films of Nylon 6,6 and PVDF, with the synthesized CCTO, are prepared using spin coating technique. Calcium carbonate (CaCOa), copper oxide (CuO), and titanium oxide (TiO4) (Ca:Cu:Ti in the ratios of 1 :3:4) were mixed in distilled water using magnetic stirring for 10 minutes. The mixture was then sonicated at 70 °C for 6 hours in an ultrasonic bath. After centrifugation, the precipitate was collected and dried at 120 °C for 5 hours. To achieve phase pure CCTO nanoparticles with complete crystallization, the powder was calcined at 900 °C for 4 h. Finally, the calcined product was grounded using an agate mortar and then planetary ball milled with distilled water as the medium to achieve nanosized particles.

[0084] In yet another embodiment of the present invention, describes the preparation of PVDF composite films. 15 wt.% bare PVDF solution was prepared by dissolving PVDF powder in DMF by magnetic stirring at 60°C for 30 minutes, then at room temperature for 10 hours. To prepare PVDF composite film, different wt.% (0.5 - 2 wt.%) of the dielectric ceramic filler (CCTO), CCTO nanoparticles were initially dispersed in DMF by ultrasonication for 1 h. 15 wt.% PVDF powder was added to itPT / 2026 / 11087

[0085] and magnetically stirred at 60 °C for 30 min, then at room temperature for 24 h to prepare a well-mixed suspension. The pure PVDF solution and CCTO filler mixed suspensions were spin-coated on the PET side of ITO-coated PET, at a rotation speed of 850 rpm for 60 s followed by drying in an oven at 70°C for 1 h, and named bare PVDF and CCTO / PVDF films respectively.

[0086] In yet another embodiment of the present invention, describes the preparation of Nylon 6,6 composite films. 2 wt.% Nylon 6,6 solution was prepared by dissolving Nylon 6,6 granules in a 2:3 mixture of methanol and meta cresol in an oven at 75°C for 16 hours. Different wt.% (0.5 - 2 wt.%) of synthesized CCTO (high dielectric filler) particles were added into it and magnetically stirred for 24 h at 65°C to yield a well-mixed suspension. As prepared Nylon solution, and ceramic filler mixed suspension were spin-coated on the ITO side of ITO-coated PET, at 400 rpm for 60 s followed by curing at 110°C for 15 min, and named bare Nylon 6,6 as well as CCTO / Nylon 6,6 films respectively.

[0087] In yet another embodiment of the present invention, flexible transparent triboelectric nanogenerator and a spring-assisted rigid triboelectric nanogenerator are fabricated with an effective contacting area of 4 cm2and 16 cm2respectively (Figure 1). Mylar sheet is used as the support case for the flexible triboelectric nanogenerator with a separation gap of 5 mm, whereas acrylic sheet is used for spring-assisted rigid triboelectric nanogenerator with a separation gap of 2 mm. The tribopositive and tribonegative layers of the triboelectric nanogenerator were made of Nylon 6,6 -based and PVDF - based flexible films respectively. ITO (Shilpent, India) serves as the transparent electrode on both sides. The copper leads are connected to the double sided conducting adhesive copper tape (3M Co.) to provide an external connection for measurements. Where the energy generation, totally based on the amalgamation of triboelectrification and electrostatic induction, is as general (Figure 2).

[0088] In yet another embodiment of the present invention, describes the initial enhancement in the peak-to-peak output performance of bare PVDF and Nylon 6,6 based flexible transparent triboelectric nanogenerator from 280 V to 1490 V and 2 pA to ~12 pA after introducing a PET interlayer between the PVDF film and ITOPT / 2026 / 11087

[0089] electrode, which is 5.3- and 6-times enhancement in comparison to device without interlayer, respectively (Figure 3). A peak instantaneous power density of 3.17 W / m2delivered, when the external load resistance is 100 MQ. The PET interlayer sandwiched between PVDF film and the ITO electrode facilitates effective charge separation, reducing the chance of charge recombination, and ensuring consistent and reliable charge transfer over repeated cycles of operation, resulting in stable and long-lasting output performance.

[0090] In yet another embodiment of the present invention, describes the influence of dielectric ceramic filler concentration on the output performance of flexible triboelectric nanogenerators fabricated with one material bare and the other composite film. The increase in dielectric constant via the addition of the ceramic filler concentration is measured and represented in Figure 4. Afterwards, the output performance of flexible triboelectric nanogenerator with composite films of Nylon 6,6 with CCTO dielectric filler as tribopositive material with bare PVDF as counter material is investigated by varying the dielectric filler wt.% from 0 - 2 wt.%. The output performance of bare PVDF and CCTO / Nylon 6,6 composite film-based flexible triboelectric nanogenerator shows an increasing trend with CCTO wt.% from 0 - 1 wt.% and saturates with a peak-to-peak output voltage of 2.6 kV and a peak-to-peak short circuit current of 33 pA. However, when the wt.% of CCTO further increases from 1 to 2 wt.%, the output voltage and short circuit current decrease to 1.73 kV and 13.5 pA peak-to-peak, respectively (Figure 5a & 5b). Furthermore, the output performance of flexible transparent triboelectric nanogenerator with PVDF composite films and bare Nylon 6,6 film is analyzed (Figure 5c & 5d). Where CCTO wt.% optimization for CCTO / PVDF composite film and bare Nylon 6,6 film-based flexible triboelectric nanogenerator is performed. In which, flexible triboelectric nanogenerator with 0.75 wt.% CCTO in PVDF generates a maximum output voltage of > 3 kV and a short circuit current of > 35 pA (peak-to-peak). This output represents a 11.3-fold and 18-fold enhancement in the output voltage and current, respectively, after intermediate layer embedding and dielectric tuning. As the wt.% of CCTO in PVDF is increased to 1 wt.%, 1.5 wt.%, and 2 wt.%, the output voltage is lowered to 1.7 kV, 1.66 kV, and 1.55 kV and the short circuit current reduced to 20 pA, 19 pA, and 13 pA, respectively. After adding 0.75 wt.% CCTO to PVDF film, the instantaneous power density goes up to > 20 W / m2, which is a > 6-fold improvementPT / 2026 / 11087

[0091] over the bare film based flexible triboelectric nanogenerator (Figure 6). These result showcase that having dielectric fillers on the PVDF side is more rewarding and advantageous in comparison to CCTO / Nylon 6,6.

[0092] These outcomes clearly show the outstanding stability and reliability 0.75 wt.% CCTO / PVDF composite film-based flexible-transparent triboelectric nanogenerator for long term practical applications. A combination where CCTO modification employed on both polymer films is not evaluated for practical purpose, since the presence of same material (CCTO) on the surface during the contact electrification between the triboelectric pair will result in decreased charge generation from the mechanical contact. Finally, the flexible triboelectric nanogenerator with the maximum output is structurally redesigned from flexible to rigid one with a separation gap of 2 mm and the contact area scaled up to 16 cm2. The triboelectric films spin coated on ITO is attached to the top and bottom acrylic sheets supported by four springs at the corners. A peak-to-peak electrical output having voltage of > 4 kVpp(Figure 7a) and short circuit current of > 45 pApp(Figure 7b) is obtained from Nylon 6,6 - CCTO / PVDF spring assisted rigid triboelectric nanogenerator. Further the load dependence (Figure 7c) as well as the capacitor charging capability (Figure 7d) is well analyzed to cement the device’s proficiency in practical application probability. Additionally, there is no apparent change in device’s output voltage and short circuit current even after continuous testing of 10,000 cycles of operation and no damage (delamination or cracks) to the film surface has been observed (Figure 8).

[0093] In yet another embodiment of the present invention, discloses the practical application of triboelectric nanogenerators for self-powered electronics and biomechanical energy harvesting. The generated electrical energy from Nylon 6,6 -CCTO / PVDF spring assisted rigid triboelectric nanogenerator has been utilized to power small electronic devices like digital calculator and thermometer and to provide sufficient lighting through a network of green LED lights (Figure 9). To demonstrate the practical wearable and portable application of the Nylon 6,6 - CCTO / PVDF spring assisted rigid triboelectric nanogenerator, the device was integrated with a shoe, enabling the conversion of biomechanical energy from footsteps into electrical energy. Here, a person with a weight of 50 kg can generate around a peak-to-peak electrical output of 900 Vppand 10 pAppwhile walking, and 1.3 kVppand 17 pAppPT / 2026 / 11087

[0094] while running (Figure 10). This allows the conversion of biomechanical energy lost during walking, jogging, or exercising on a treadmill into to useful electrical energy to instantaneously power or charge electronic gadgets. Thus, the concept of harvesting energy from footsteps during walking as well as running using a spring assisted rigid triboelectric nanogenerator is made practically possible here.

[0095] ADVANTAGES

[0096] The main advantages of the present invention are:

[0097] • The preparation of the bare and composite films and the fabrication of triboelectric nanogenerator involves facile, inexpensive, reliable, and scalable processes.

[0098] • The device serves as a green energy harvester fabricated with environmentally friendly polymers such as Nylon 6,6 and PVDF, and high dielectric ceramic filler like CCTO.

[0099] • The device exhibits transparency and flexibility, which is ideal for the optoelectronic and other applications.

[0100] • The output performance of Nylon 6,6 - PVDF film-based flexible-transparent triboelectric nanogenerator is enhanced from 280 Vppto > 3 kVppand 2 pAppto > 35 pAppwith an instantaneous power density of > 20 W / m2after adopting simple and effective strategies involving the combined effect of dielectric tuning and the intermediate layer embedding.

[0101] • The flexible-transparent triboelectric nanogenerators as well as Spring- assisted triboelectric nanogenerators exhibit stable output performance over 10,000 cycles of operation, indicating their practicality in long-term operation.

[0102] The fabricated triboelectric nanogenerator can be integrated with the footwears to harvest the squandered biomechanical energy during human motion.PT / 2026 / 11087

[0103] The above described embodiments, while including the preferred embodiment and the best mode of the invention known to the inventor at the time of filing, are given as illustrative examples only. It will be readily appreciated that many deviations may be made from the specific embodiments disclosed in this specification without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is to be determined by the claims below rather than being limited to the specifically described embodiments above.

Claims

PT / 2026 / 11087WE CLAIM:

1. A high voltage transparent triboelectric nanogenerator (TENG) comprising:a) a lower substrate, said lower substrate including:i) an ITO (indium tin oxide) layer deposited at the lower substrate of mylar sheet and acting as a positive electrode,ii) a PET (polyethylene terephthalate) layer deposited above the ITO layer,iii) a PVDF (polyvinylidene difluoride) layer filled with CCTO (calcium copper titanium oxide) nanoparticle deposited above the PET layer which acts as a negative layer;b) an upper substrate, said upper substrate including:i) an ITO (indium tin oxide) layer deposited at the upper substrate of mylar sheet and acting as a negative electrode,ii) a Nylon 6,6 layer filled with CCTO (calcium copper titanium oxide) nanoparticle deposited on top of the ITO layer which acts as a positive layer;c) four stainless steel springs located at the corners of lower substrate.wherein, in contact-separation mode, with either flexible or rigid form factors and triboelectrification between polyvinylidene fluoride (PVDF) and Nylon 6,6 flexible transparent films;wherein, the combination of intermediate layer integration and dielectric tuning of contact layers facilitate enhanced energy generation from mechanical forces.

2. The high voltage transparent triboelectric nanogenerator (TENG) as claimed inPT / 2026 / 11087claim 1 , wherein, an intermediate layer mitigates the generated triboelectric charge loss through interfacial combination with the induced charges, leading to 5.3-fold increment in voltage 6-fold increment in current values.

3. The high voltage transparent triboelectric nanogenerator (TENG) as claimed in claim 1 , wherein, the synthesis of high dielectric ceramic filler, calcium copper titanate [CaCu3Ti40i2(OCTO)] for preparation of ceramic filler-dispersed polymer (PVDF and Nylon 6,6) films with improved dielectric permittivity, and optimize the filler concentration in the polymer films are designed to enhance the output energy generation owing to the improved charge storing capability.

4. The high voltage transparent triboelectric nanogenerator (TENG) as claimed in claim 1 , wherein, an optimum percentage of CCTO i.e., 0.75 wt% embedded in PVDF layer generates a peak-to-peak electrical output having a voltage of 4.3 kVpp and short circuit current of 45 pAppfor a rigid triboelectric nanogenerator.

5. The high voltage transparent triboelectric nanogenerator (TENG) with flexible form factor in claim 1 , wherein, said high voltage transparent triboelectric nanogenerator generates high electrical output of a voltage > 3 kVpp(peak-to- peak) and a short-circuit current > 35 pApp(peak-to-peak).

6. The high voltage transparent triboelectric nanogenerator (TENG) as claimed in claim 1 , wherein, said high voltage transparent triboelectric nanogenerator having a rigid form factor and consisting of a spring-assisted structure and a triboelectric contact pair with optimal filler concentration, thereby possessing enhanced rigidity for harvesting higher magnitude force regimes.

7. The high voltage transparent triboelectric nanogenerator (TENG) as claimed in claim 1 , wherein, said high voltage transparent triboelectric nanogenerator having a rigid form factor with a contact area of 16 cm2, exhibiting stable output performance over 10,000 cycles of operation with a maximum output voltage of > 4 kVpp and a short-circuit current of > 45 pApprespectively.

8. The high voltage transparent triboelectric nanogenerator (TENG) as claimed inPT / 2026 / 11087claim 1, wherein, an optimum percentage of CCTO i.e., 0.75 wt% embedded in PVDF layer generates a maximum output voltage of 3.17 kV and a short circuit current of 36 pA (peak-to-peak) which represents a 11.3-fold and 18-fold enhancement in the output voltage and current for a flexible triboelectric nanogenerator.

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