A hybrid strain and thermal energy harvester based on an infra-red sensitive Er3+ modified poly(vinylidene fluoride) ferroelectret structure

Abstract

In this paper, a novel infra-red (IR) sensitive Er3+ modified poly(vinylidene fluoride) (PVDF) (Er-PVDF) film is developed for converting both mechanical and thermal energies into useful electrical power. The addition of Er3+ to PVDF is shown to improve piezoelectric properties due to the formation of a self-polarized ferroelectric β-phase and the creation of an electret-like porous structure. In addition, we demonstrate that Er3+ acts to enhance heat transfer into the Er-PVDF film due to its excellent infrared absorbance, which, leads to rapid and large temperature fluctuations and improved pyroelectric energy transformation. We demonstrate the potential of this novel material for mechanical energy harvesting by creating a durable ferroelectret energy harvester/nanogenerator (FTNG). The high thermal stability of the β-phase enables the FTNG to harvest large temperature fluctuations (ΔT ~ 24 K). Moreover, the superior mechanosensitivity, SM ~ 3.4 VPa−1 of the FTNG enables the design of a wearable self-powered health-care monitoring system by human-machine integration. The combination of rare-earth ion, Er3+ with the ferroelectricity of PVDF provides a new and robust approach for delivering smart materials and structures for self-powered wireless technologies, sensors and Internet of Things (IoT) devices.

Catalysis of the Thermal Decomposition of Transition Metal Nitrate Hydrates by Poly(vinylidene difluoride)

“…In all cases, the diffractograms could be fit with six Gaussian peaks in the range of 5 to 45° 2θ, as shown in Figure S2 . In undoped PVDF, these peaks were found at 18.6° (202/020), 35.1° (200), and 39.5° (211), assigned to α-phase crystallites, and 20.3° (200/110), assigned to the β-phase [ 6 , 7 , 14 , 19 , 20 , 21 , 22 , 23 ]. The other two peaks, found at 19.4° and 39.5° were very broad and are assigned to the amorphous background.…”

“…It has been reported for several years that addition of dopants to PVDF leads to deposition of films with significantly modulated electromagnetic properties [3,5,7,[10][11][12][13][14][15][16]. For example, when PVDF is doped with Co(II) ions, the metal ions weakly bond with fluorine atoms of PVDF, which leads to a cooperative effect aligning the bond dipole moments of the polymer chain that leads to a higher fraction of β-phase [13].…”

Self-Polarization of PVDF Film Triggered by Hydrophilic Treatment for Pyroelectric Sensor with Ultra-Low Piezoelectric Noise

“…Recently, various methods have been developed to realize self-polarized PVDF films without undergoing thermal poling, including casting [21–25], spin coating [26, 27], Langmuir-Blodgett (LB) deposition [28], electrospinning [29–35], and depositing onto aqueous salt solution [36]. In general, self-polarization of the PVDF films can be observed through the above techniques due to different mechanisms, such as the salt-assisted [21–25], hydrogen-bonding interaction [21–25, 27, 36], built-in field [26] or strong electric field [29, 35] during deposition, and stretching during coating [26, 28, 36]. Yet, most of these methods only focused on the piezoelectric performance of PVDF films and neglected its pyroelectric property.…”

“…Yet, most of these methods only focused on the piezoelectric performance of PVDF films and neglected its pyroelectric property. In addition, spin coating and LB techniques were only applicable for ultra-thin films [26, 28], while the casting method needed salt additive to achieve self-polarization [21–25], and the polarization mechanism of the electrospinning required further understanding [29–35]. When it turns to the issues of the sensor, selectively poling of ferroelectric ceramic-doped PVDF composites is a common method to decrease the effect of environmental vibration noise [37, 38].…”

Ferroelectric Materials Based Coupled Nanogenerators

“…The material and structure designs are crucial for the improvement in the output of PyENGs because the pyroelectric coefficients have small values. Improving these various approaches has already been reported, including the control over crystallinity for im-proving pyroelectric coefficient [185], introducing strain coupling effects [186], or polymer modifications [187]. Kim et al [185] used high dipole moment solvents for improving the crystallinity and pyroelectric coefficient of P(VDF-TrFE); the solvents they used were THF (tetahydrofuran), MEK (methylethylketone), DFM (dimethylformamide), and DMSO (dimethylsulfoxide).…”