1 Introduction

With the technological advancement, flexible, wearable and, miniaturized microelectronic devices with diverse functionality are rapidly becoming the part of our mundane life by affecting various aspects of human life from health monitoring, and entertainment to information and communication technology [1, 2]. One of the important factors for continuous and stable operation of these flexible and wearable electronic devices is the sustainable power supply. Till now, batteries have been used as one of the most reliable and economical sources to supply power to these electronic devices but their frequent recharging and replacement process, bulky nature and disposal difficulty are becoming challenge for their long term application and environmental safety [3, 4]. This problem can be overcome by scavenging the energy from our living environment as there are ample green sources of energy present in our environment including motion or movements, vibrations, waves, solar energy, wind, and thermal energy sources which are capable of generating electricity [5,6,7,8]. Among which scavenging mechanical energy particularly from the human body, where sufficient energy is generated by human motion can become potential alternative to supply power to the portable, and wearable electronic device. In this regard, piezoelectric nanogenerators (PNG) have gathered significant attention because of their outstanding ability to convert tiny and irregular mechanical energy from running, walking, typing, muscle movements, and respiration etc. into electricity with the help of piezoelectric materials [9,10,11,12]. Several PNG have been developed over the past few years using PZT, BaTiO3, GaN, LiNbO3, PVDF, and its copolymers to increase the energy conversion efficiency since the invention of first PNG by Prof. Zhong Lin Wang group in 2006 [13,14,15,16,17]. However, inorganic piezoelectric materials suffer from poor toughness/ brittleness, low durability, toxicity and heavy weight which restrict their application in flexible piezoelectric energy harvesting device. In this regard, piezoelectric polymer for example PVDF and its copolymer is a good choice for fabricating flexible nanogenerator due to its flexible, lightweight, biocompatibility, and conformable nature makes them favorable to design flexible device. The electroactive polar (i.e. β and γ) phases are responsible for facilitating the piezoelectric properties in PVDF film. The piezoelectric response of the PVDF can be further enhanced by several mechanisms, such as, electric poling, mechanical stretching, and the addition of nanofillers i.e. carbon based materials, metal nanoparticles (NPS), metal oxide, and ceramics in polymer matrix which helps in nucleation of electroactive polar phase [16, 18]. Anand et al. synthesized the PVDF composite films via the solution casting method in which addition of rGO in the PVDF matrix and applying the UV Visible light exposure on the sample enhances the piezoresponse of the polymer composite films upto 8 times in comparison to pristine PVDF film and hence producing a maximum voltage of ~ 1.9 V [19]. Hu et al. fabricated a wearable piezoelectric nanogenerator using rGO/PVDF-TrFE film and uses in situ polarization method to increase the energy harvesting performance of the device [20]. The fabricated nanogenerator can produce a maximum voltage, current, and power density of 8.3 V, 0.6 µA, and 28.7 W/m3respectively. Also, it has been observed from the literature that doping of rGO with other atoms, such as Fe reported by Karan et al. increases the output performance of the PENG by enhancing the electrical properties [21]. In the reported work, the addition of Fe doped rGO not only helps in the nucleation of electroactive γ phase to ~ 99% (± 0.18 of relative proportion) in PVDF but also increases the surface conductivity up to ~ 3.30 × 10−3 Scm−1as a result enhance piezoelectric properties of nanocomposite films. Also, the doping of nitrogen, iron, and co-doping of two different heteroatoms in rGO are also reported to enhances the piezoelectric performance of PVDF based nanocomposite film [22, 23]. However, studies on the enhancement of piezoelectric properties in boron doped rGO (B-rGO) have been found to be relatively limited. Furthermore, boron doping in rGO framework leads to redistribution of the energy density, which alters the band structure, charge transfer characteristics, and electronic properties, facilitating it applications in numerous fields, such as, supercapacitors [24], batteries [25], solar cell [26], biomedical applications [27, 28] and can also affects the piezoelectric response of rGO.

In the current study, we have reported a flexible PVDF composite film based piezoelectric nanogenerator for harnessing the mechanical energy from the human body. Firstly, a PVDF based nanogenerator is fabricated, and then to enhance its output performance rGO and boron doped rGO are added in polymer matrix. Then output performance of all the fabricated PNG are compared which shows that incorporation of conducting nanofillers in PVDF matrix improves the output performance. A maximum open-circuit voltage, short-circuit current and power density of 13.8 V, 5.5 µA and ~ 42.3 µW/cm2 is obtained for PVDF/boron doped rGO (PBR) nanocomposite film based piezoelectric nanogenerator. To demonstrate the PNG’s practical applicability, energy produced by PNG is stored in 1µF capacitor and utilized to power LEDs connected in series. Finally, the fabricated device is demonstrated to harness energy from daily life activities of human body such as wrist bending, leg folding, foot tapping and elbow bending.

2 Synthesis and experimental details

The rGO is synthesized by our previous reported paper using hydrothermal approach [22]. For the synthesis of boron doped rGO, 1 g of boric acid is mixed into an aqueous solution of GO and sonicated for 30 min for homogeneous dispersion. The prepared solution is then transferred to Teflon lined autoclave and kept in oven at 180 °C for 12 h. After being washed multiple times with DI water and ethanol, the resulting product is kept in an oven overnight at 60 °C for drying to get nanosheets of boron doped rGO (B-rGO). Subsequently, a simple drop casting method is used for synthesis of the PVDF and PVDF nanocomposite films. First, 1 g of PVDF is mixed in 10 ml N,N-dimethylformamide (DMF) with the help of magnetic stirrer until PVDF powder is completely dissolved in the solvent to obtain transparent solution. Then 10 mg of B-rGO is added to the above solution and stir for 45 min. After that the resultant solution is drop casted on clean glass substrate with the help of micropipette and placed in oven for 2 h at 90 °C to remove any solvent. Then after natural cool down, the films are dipped in DI water to obtain freestanding films. The rGO doped film is also prepared by the same procedure by adding 10 mg of rGO in the PVDF/DMF solution.

2.1 Fabrication of the piezoelectric nanogenerator

To fabricate PNG, first the PVDF and PVDF composite films are cut into the requisite shape and aluminum electrode of thickness 100 nm is deposited on both sides of film of area 2 × 2 cm2 with thermal evaporation technique. After that two copper wires are drawn from the top and bottom aluminum electrode surface for the external connection and finally the entire device is encapsulated with Kapton tape. The detailed schematic diagram showing the fabrication of piezoelectric nanogenerator has already been published by our group [22].

3 Characterization techniques

Firstly, synthesized powder samples of rGO and B-rGO are characterized by X-ray diffractometer and Raman spectroscopy technique using Rigaku, Ultima diffractometer and WiTec alpha 300 RA model with a laser source of 532 nm wavelength. X-ray photoelectron spectroscopy (XPS) measurements are recorded by Nexsa base spectrometer with Aluminium Kα source for chemical composition analysis. The surface morphologies of the samples together with the energy-dispersive X-ray spectroscopy (EDS) are observed under a field emission scanning electron microscopy via Nova Nano SEM. Fourier transform infrared spectroscopy (FTIR) spectra of the polymer composite films are obtained by Perkin Elmer Spectrum II spectrometer. The Marine India PE loop tracer is used to measure polarization versus electric field (P–E) loops and YE2730A d33 meter is used to measure the piezoelectric coefficient (d33) of PVDF and PVDF composite films. The crystallinity of the films are measured using Differential Scanning calorimeter (DSC 8000, Perkin Elmer). Finally, in order to measure output performance of PNG, the VOC and ISC measurements are carried out by Tektronix MDO500 oscilloscope and Keithley DMM7510 digital multimeter.

4 Results and discussion

Figure 1a shows the XRD pattern of synthesized rGO and B-rGO samples. Both the samples show the diffraction peak corresponding to (002) plane which is characteristic peak of graphitic materials. For rGO, the peak corresponding to (002) plane is appeared at 2θ = 24.84°, whereas in B-rGO case the peak is shifted right and appear at 25.14°. The corresponding value of interlayer spacing for rGO and B-rGO is 3.58 Å and 3.53 Å respectively. The decrease in the interlayer spacing can be attributed due to the fact that when we dope boron atom in rGO matrix, it gives rise to strain because of the different atomic size of boron and carbon atom resulting in peak shift [29, 30]. Also, the reduction of π electron density between graphene planes may be the another possible reason for low interlayer spacing in B-rGO due to the replacement of carbon by boron atom [31].

Fig. 1
figure 1

a XRD and b Raman spectra of synthesized rGO and B-rGO samples

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As we know, the crystallinity and homogeneity of the rGO and heteroatom doped rGO is highly sensitive to the synthesis route. Therefore, to evaluate the degree of disorder within the carbon samples, Raman analysis for the rGO and B-rGO are collected at an excitation wavelength of 532 nm. The Raman spectra of all samples exhibit two major Raman peaks at 1344 and 1586 cm−1 corresponds to the D and G band and a wide 2D-band around 2800 cm−1 corresponding to the carbon structure in rGO as depicted in Fig. 1b. In the Raman spectra, D band stems from the structural defects and disorder structure in graphitic lattice while G bands ascribed to inplane stretching of C=C bonds and first order E2g optical mode of graphite. To further deduce the degree of disorder and defects present in rGO sample after doping, ID/IG ratio of the rGO and B-rGO is calculated which shows that when we dope the boron atom in rGO, the ID/IG ratio increases slightly from 1 to 1.01. This slight increment in the value of ID/IG ratio shows the successful doping of boron atom and increased amount of disorder in sp2 domains and structural defects in B-rGO [32, 33].

To further support the successful incorporation of boron atom in rGO, the X-ray photoelectron spectroscopy (XPS) analysis is carried out for rGO and B-rGO samples where in the survey spectrum, rGO has only C1s (285.2 eV) and O1s (532.9 eV) peaks, whereas for B-rGO an additional B1s (192.7 eV) peak is observed showing that boron atoms are bonded to rGO network (Fig. 2a). Figure 2b shows the high resolution deconvoluted C1s spectra of rGO which is divided into four peaks at different binding energy levels (284.5, 285.4, 288.2, and 290.6 eV). The peak at 284.5 eV corresponds to sp2 hybridized C–C bond, while the peaks at 285.4, 288.2, and 290.6 eV corresponds to C–O, C=O and O–C=O bonds respectively [22, 29, 34]. Figure 2c shows the high resolution C1s spectra of B-rGO, where B-rGO sample have all the functional groups as that in case of rGO with the exception that peak at 290.6 eV is shifted to 290.1 eV and this new peak corresponds to the C–O–B bond. Figure 2d shows the high resolution B1s spectra of B-rGO, which is deconvoluted in three peaks at binding energies 191.3, 192.4 and 193.3 eV corresponding to BC3, BC2O and BCO2 bond respectively [26, 35]. The B1s spectra of B-rGO demonstrates that boron can exist in three different form, first is by substitution of carbon atom by boron atom in the rGO network to form bond BC3, second is co-doping with the oxygen to form BC2O bond which creates nanovoids in layer and third is BCO2 bond resulting from the formation of functional groups [36]. These results not only confirm the successful incorporation of boron atoms in rGO network but also show that the interlayer spacing increases and more defects are introduced in rGO network.

Fig. 2
figure 2

a XPS survey spectra of rGO and B-rGO, High resolution deconvoluted C1s spectra of b rGO and c B-rGO, d B1s spectra of B-rGO

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For structural and morphological analysis, FESEM micrographs are obtained for rGO and boron doped rGO samples. As depicted in Fig. 3a–b, rGO exhibit of randomly aggregated layered structure where few layer of sheets that are closely associated with one another and after doping of boron atom in rGO the aggregation increases. In addition, Energy Dispersive X-ray spectroscopy (EDX) analysis have also been carried out on B-rGO for the elemental analysis of the sample. The EDX spectra confirms the presence of C, O, and B elements for B-rGO sample is illustrated in Fig. 3c–f that further confirm the presence of boron atom in rGO network. After successful synthesis of rGO and B-rGO samples, they are mixed in PVDF and DMF solution to fabricate the polymer composite films. The samples of pure PVDF, rGO doped PVDF and B-rGO doped PVDF are described as P, PR and PBR respectively.

Fig. 3
figure 3

Morphological characterization of the synthesized a rGO and b B-rGO powder sample. c EDX spectra and d elemental mapping of C, O, and B atom present in the B-rGO sample

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To confirm the existence of different phases in pristine PVDF and PVDF composite films, XRD and FTIR analysis is carried out. Figure 4a depicts the XRD pattern of P, PR and PBR composite films where all the samples exhibit two characteristic peak. The presence of a small characteristic peak at ~ 18.4° correspond to (100) plane belongs to the non-polar α phase, whereas the presence of sharp intense peak at ~ 20.4° corresponds to (200) plane of polar β phase of the PVDF [37, 38]. It can be clearly seen from the graph, that the intensity of peak at ~ 20.4° grows, which proves enhanced polar phase in PVDF with addition of rGO and B-rGO as a nanofillers materials. Moreover, to further investigate the crystal phases of PVDF, FTIR analysis is carried out on the synthesized polymer and polymer composite films. Figure 4b shows the FTIR spectra of pristine PVDF and PVDF composite films, where peaks at 612, 764, 795, and 1382 cm−1 are attributed to non-polar α phase with trans-gauche-trans-gauche (TGTG) conformation, whereas the peaks at 840 cm−1 and 1275 cm−1 are related to electroactive polar β phase of PVDF and arises due to the asymmetrical stretching of –CF2 and oscillating vibration of –CH2 dipoles [39, 40]. In comparison to pristine PVDF film, the intensity of absorbance peaks corresponding to α phase is decreasing in PR and PBR films indicating that when rGO and B-rGO are doped in PVDF matrix, they aid in the formation of crystalline phase. The relative content of the polar phases in PVDF is calculated with the help of Lambert-Beer law using absorption bands at 761 cm−1 and 840 cm−1 and is given by the equation.

$$F\left(\beta \right)= \frac{{A}_{\beta }}{\left(\frac{{k}_{\beta }}{{k}_{\alpha }}\right){A}_{\alpha }+{A}_{\beta }}\times 100\%,$$

where, \({A}_{\alpha }\) and \({A}_{\beta }\) are the absorbance of α and β phase at 761 cm−1 and 840 cm−1 and \({k}_{\alpha }\) and \({k}_{\beta }\) are the absorption coeffecient at respective wavenmber (\({k}_{\alpha }\) = 6.1 × 104 cm2 mol−1, \({k}_{\beta }\) = 7.7 × 104 cm2 mol−1) and F(β) represents the relative fraction of β phase [41]. The value of F(β) obtained for pristine PVDF is ~ 69% and after loading the rGO and B-rGO the value of F(β) becomes ~ 77% and ~ 80% respectively. The substantially increased value of F(β) can be understood by the fact that when we add rGO and B-rGO in the PVDF matrix, there is strong interaction between the surface charges arise due to decolalized π electron, boron atom and oxygen containing functional group in rGO and B-rGO with the –CH2 and –CF2 dipoles of the polymer chain [21, 42]. The fluorine group of PVDF interacts with boron and oxygen containg functional groups present on basal plane of B-rGO, allowing PVDF chain to crystallize on their surface in trans-trans-trans-trans(TTTT) conformation, faciliating the tranformation of non-polar α phase to the polar β phase. The proposed mechanism for the formation of electroactive polar phase after doping is shown in Fig. 4g. Thus, it can be concluded that the addition of rGO and B-rGO acts as a nucleating agent, which helps in inducing electroactive polar phase in PVDF segment by rotating the polymer chain in all trans configuration. Furthermore, to verify the enhanced piezoelectric properties of the composite films, a comparison between the polarization versus electric field (P–E) hysteresis loop analysis is done on the films to reveal the effect of rGO and B-rGO doping on the ferroelectricity of nanocomposite films. The P–E loops show that after incorporating rGO and B-rGO in PVDF matrix, the ferroelectric properties of polymer film improve. The value of remnant polarization which indicates the internal dipole moment per unit volume when applied electric field is zero obtained from the P–E loops are 0.23, 0.26 and 0.31 µC/cm2 for P, PR and PBR films respectively as shown in Fig. 4c. The improved value of remnant polarization after addition of rGO and B-rGO illustrate that addition nanofillers helps in alignment of dipole in the PVDF film and a maximum value of the remnant polarization corresponds to PBR composite film. In order to further confirm the enhancement in the piezoelectric properties of PVDF after doping of rGO and B-rGO, the piezoelectric strain coefficient d33 is measured with the help of Sino Cera YE2730 d33 meter, which relates the electric field produced for an applied electric stress. The value of d33 for P, PR and PBR films are 4, 4.4 and 5.3 pC/N respectively as shown in Fig. 4h. The increase in the value of d33 in the composite is attributed due to increase in interfacial polarization after addition of the rGO and B-rGO in the PVDF matrix which is in agreement with P–E and FTIR studies. The effect of addition of rGO and B-rGO on the crystallization and melting temperature of PVDF composite films were analyzed by DSC as the piezoelectric behavior of the nanocomposite films are dependent on the crystalline structure as well as the stability of the electroactive polar phase of the nanocomposite films [43]. Figure 5a–b shows the DSC thermographs of pristine PVDF and PVDF nanocomposite films, which shows that when we add nanofillers in PVDF matrix, the melting temperature (Tm), melting enthalpy (ΔHm), and crystalline temperature (Tc) increases gradually as shown in Table 1. The shifting of peak towards high temperature is attributed to the transformation from α phase to β phase which is in accordance with XRD and FTIR studies [44]. The percentage crystallinity is determined by the following equation.

$${{\chi }}_{{c}}\left({\%}\right)=\frac{{\Delta {H}}_{{m}}}{(1-{\varphi }) {\Delta {H}}_{{m}}^{^\circ }}\times 100{\%},$$
Fig. 4
figure 4

a–c XRD, FTIR and P–E loops of the pure PVDF (P), PVDF/rGO (PR) and PVDF/B-rGO films, respectively, d–f FESEM images showing the morphology of P, PR and PBR films, g A schematic representation showing the interaction between dipoles present in PVDF and the filed B-rGO in the PVDF matrix, h piezoelectric strain coefficient d33 of P, PR and PBR films

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Fig. 5
figure 5

DSC a heating and b cooling curves of PVDF and PVDF nanocomposite films

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Table 1 The DSC parameters of pristine PVDF and PVDF nanocomposite films
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where, \({\Delta {H}}_{m}\) is melting enthalpy, \({\phi }\) is filler loading percentage, and \({\Delta {H}}_{m}^{^\circ }\) is the melting enthalphy of 100% crystalline PVDF (i.e. 104.5 J/g). The calculated value of \({\chi }_{c}\) for pristine PVDF and PVDF nanocomposite films are shown in Table 1. The percentage crystallinity also increase from ~ 27% in pristine PVDF film to ~ 32% in PBR film. Furthermore, to check the surface morphology of the polymer and polymer composite films, FESEM images are taken for the PVDF and PVDF nanocomposite films (Fig. 4d–f) which shows that rGO and B-rGO nanosheets are evenly distributed in the PVDF polymer matrix without aggregation.

The PNG structure with the corresponding working principle is illustrated in Fig. 6. In initial state, when no force is imparted on device (Fig. 6a), PNG does not deliver any electrical output due to presence of the existing unpolarized electric dipoles in the film. Therefore, when we start to apply force on device (Fig. 6b), film starts deforming to polarize the electric dipoles inside the film and due to polarization effect, electric charges are induced on both electrodes, causing charges to flow from bottom to top electrode. When force is removed (Fig. 6c) the compressive stress fades away in the film leading the electron to flow in the opposite direction until PNG device returns to its initial state. This periodic process results in generation of positive and negative potential cycles in output of nanogenerator.

Fig. 6
figure 6

 A schematic showing the working mechanism of piezoelectric nanogenerator

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The piezoelectric energy harvesting performance of PNG device is analyzed by periodic tapping of nanogenerator with the help of the dynamic shaker and measuring the corresponding open-circuit voltage (VOC) and short-circuit (ISC) current with the help of the oscilloscope and digital multimeter. In our previous study, we have demonstrated that when we tap the nanogenerator at different frequency, maximum voltage is obtained corresponding to 6 Hz tapping frequency. Therefore, in this paper we have measured the open-circuit voltage and short-circuit current of P, PR, and PBR films at 6 Hz frequency only. Figure 7a–c depicts the measured open-circuit voltage of the fabricated PNG, in which maximum voltage of 13.8 V is produced by PBR film based PNG, whereas pristine PVDF and PR film based PNG produce an output voltage of 7.6 and 12.2 V respectively. The value of rectified short-circuit current obtained for P, PR and PBR film based PNG are 2.6 µA, 4.72 µA and 5.57 µA respectively (Fig. 7d–f). Furthermore, the effect of tapping frequency on the output voltage of PBR film based PNG is also examined which also further verify that maximum output voltage corresponds to the 6 Hz frequency as shown in Fig. 8a. Among all the fabricated device, PNG made by PBR film show maximum output in comparison to PVDF and PR film based PNG. The enhanced performance of PBR film based PNG can be ascribed due to the following aspects. First, adding boron doped rGO in PVDF helps in nucleation of β phase which is supported by XRD, FTIR and P–E studies. Second, it has been reported in the literature that selective surface adsorption of atoms in graphene can induce the piezoelectricity in it by breaking the inversion symmetry, therefore it is possible that when we add boron atom in rGO it will break the inversion symmetry and induce piezoelectricity in it [45]. Third, rGO is conducting in nature therefore when we add it in the polymer matrix it forms conducting channels which helps in the better charge transfer as a result increase the output performance of the PBR film based PNG device [46]. The variation of the output voltage of P, PR PBR film based PNG devices across the varied load resistance are shown in Fig. 8b, where maximum voltage is corresponding to 8 MΩ resistance after that voltage first saturates and then start decreasing. Figure 8c depicts the power density curves of the corresponding films, with a maximum power density of ~ 42.3 µW/cm2 is attained for PBR based PNG device. As the output of the PNG is AC in nature, therefore to store the generated energy a bridge rectifier is utilized to convert AC voltage to DC voltage. Figure 8d shows the energy generated by PBR film based PNG device and is stored in different capacitors (1, 4.7 and 10 µF). It is clearly seen from the graph that 1 µF capacitor can charge upto ~ 4.6 V in 60 s while 4.7 and 10 µF capacitor can charge upto 2.8 V and 1.4 V respectively. The stored energy is then further used to light up different LEDs and their corresponding circuit design is shown in Fig. 8e. The PBR film based PNG device can light up maximum 5 LEDs with the digital picture illustrated in Fig. 8f and corresponding video is placed in supplementary. Furthermore, the as fabricated nanogenerator is utilized to harness biomechanical energy from human body by attaching it to different parts of the body and a schematic representation of human body parts from which energy has been harvested is shown in Fig. 9a. Figure 9b–d illustrates the output voltage generated by PNG by tapping it with one finger, two finger and thumb. The variation of the tapping with finger in slow, moderate and high speed is also illustrated in Fig. 9j. The output voltage generated by nanogenerator by clapping and attaching it to wrist, elbow, knee, and tapping it with foot are illustrated in Fig. 9e–i. We also measured PNG’s output voltage by bending elbow at various angles (30°, 45° and 90°) as illustrated in Fig. 9k. The above results demonstrate the flexible PBR film based PNG is an effective device that can harness biomechanical energy from the human motion. Thus, by harvesting the energy associated with these various biomechanical motions, it is possible to design a pervasive, sustainable and environmental friendly energy solution for the bioelectronics which will revolutionize the future of wearable electronics in upcoming era of IoT and artificial intelligence [47,48,49].

Fig. 7
figure 7

a–c Open-circuit voltage and d–f rectified short-circuit current measurements of P, PR, and PBR film based PNG device

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Fig. 8
figure 8

a The measured output voltage of PBR film based PNG as a function of frequency. b Variation of output voltage and c power density as a function of load resistance, d Charging of 1, 4.7, and 10 µF capacitor by the generated voltage of PBR based device, e A circuit diagram for storing the energy generated by PNG in the capacitor to power up LEDs f digital photograph showing LEDs powered by PNG

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Fig. 9
figure 9

a A schematic representation of different parts of human body from which energy can be harvested. The output voltage generated by PBR film based PNG by b one finger, c two fingers, d thumb tapping, e clapping, f wrist bending, g elbow bending, h knee folding, and i foot tapping, j variation in the output performance of PNG by slow, moderate and fast finger tapping, k The voltage produced by PNG by bending elbow at different angles

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5 Conclusion

In this work, rGO and B-rGO are successfully synthesized by the hydrothermal technique and are incorporated in the PVDF matrix to synthesize polymer nanocomposite films. It is realized that incorporating rGO and B-rGO into the PVDF matrix improves device piezoresponse by increasing nucleation, which improves content of β phase in PVDF nanocomposite film. A maximum open-circuit voltage and short-circuit current of 13.8 V and 5.5 µA is produced by the boron doped rGO/PVDF film based device whereas pristine PVDF based PNG can only generate an output voltage and current of 7.6 V and 2.6 µA, respectively by tapping the nanogenerator with 6 Hz frequency. The practical applicability of the as fabricated nanogenerator is demonstrated by storing the harvested energy in the capacitor which is used to power up 5 LEDs connected in series. The fabricated PNG also demonstrated energy harvesting from the human movements, which includes finger tapping, foot tapping, elbow bending, wrist movements and leg folding. Hence, the current study proposes an effective strategy of using biocompatible PVDF flexible films for harvesting the various biomechanical energy for biomedical sector such as drug delivery, cell stimulation, body patchable device, sensors, and so on, paving a new path for designing a self-powered system by providing a pervasive energy solution for smart and versatile wearable bioelectronics devices.