TY - GEN A1 - Ghosh, Sujoy Kumar A1 - Biswas, Anirban A1 - Sen, Shrabanee A1 - Das, Chittaranjan A1 - Henkel, Karsten A1 - Schmeißer, Dieter A1 - Mandal, Dipankar T1 - Yb3+ Assisted Self-Polarized PVDF Based Ferroelectretic Nanogenerator: A Facile Strategy of Highly Efficient Mechanical Energy Harvester Fabrication T2 - Nano Energy N2 - Ytterbium (Yb3+) assisted porous poly(vinylidene fluoride) (PVDF) composite film comprising flexible ferroelectretic nanogenerator (FTNG) is highlighted where traditional poling treatment is completely avoided. The piezoelectric output of FTNG is realized by the co-operative activity of self-polarized -CH2/-CF2 dipoles with porous electret-like structure in the composite film. Owing to extraordinary ferroelectric and dielectric properties, FTNG is acting as a highly efficient mechanical energy harvester. It is capable to capture several forms of abundant mechanical energy arising from humanfinger movements, machine vibrations and sound waves. As a proof of concept, under compressive deformation, FTNG is enable to instantly powers up several consumer electronics and thus provides a promising strategy for achieving self-powered electronic devices. KW - PVDF KW - Yb 3+ KW - Porous ferroelectret material KW - Self-polarization KW - Ferroelectretic nanogenerator KW - Mechanical energy harvester KW - Self-powered electronics Y1 - 2016 U6 - https://doi.org/10.1016/j.nanoen.2016.10.042 SN - 2211-2855 VL - 2016 IS - 30 SP - 621 EP - 629 ER - TY - GEN A1 - Biswas, Anirban A1 - Henkel, Karsten A1 - Schmeißer, Dieter A1 - Mandal, Dipankar T1 - Comparison of the thermal stability of the α, β and γ phases in poly(vinylidene fluoride) based on in situ thermal Fourier transform infrared spectroscopy T2 - Phase Transitions N2 - The electroactive β phase of poly(vinylidenefluoride) (PVDF) is induced due to the aging time of PVDF solutions. The feasibility of the combination of the three crystalline polymorphs (α, β and γ) is demonstrated where their relative proportion within the PVDF film can be tailored by the simple monitoring of the preparation conditions. To identify all these phases, Fourier transform infrared (FT-IR) spectroscopy is carried out and it is spotlighted that the vibrational bands at 510 and 841 cm-1 are not sufficient to state the formation of the β phase. The main aim of this work is devoted to develop a better understanding on the thermal stability of these several phases of PVDF, which has a longstanding ambiguity persisting in this area. It has been found that the in situ thermal FT-IR spectroscopy is one of the best alternatives to understand this important issue. It is ascertained that the β phase is the least thermally stable phase among α, β and γ phases, whereas the γ phase is the most thermally stable phase. KW - PVDF KW - thermal stability KW - β-phase KW - infrared spectroscopy KW - in situ thermal FT-IR study Y1 - 2017 U6 - https://doi.org/10.1080/01411594.2017.1337902 SN - 0141-1594 SN - 1029-0338 VL - 90 IS - 12 SP - 1205 EP - 1213 ER - TY - GEN A1 - Biswas, Anirban A1 - Garain, Samiran A1 - Maity, Kuntal A1 - Henkel, Karsten A1 - Schmeißer, Dieter A1 - Mandal, Dipankar T1 - Influence of In situ Synthesized Bismuth Oxide Nanostructures in Self-poled PVDF-based Nanogenerator for Mechanical Energy Harvesting Application T2 - Polymer Composites N2 - A self-poled piezoelectric nanogenerator (NG) based on bismuth oxide (Bi2O3) nanostructures (BNS)-doped poly(vinylidene fluoride) (PVDF) is demonstrated. The in-situ formation of BNS incorporated in the PVDF matrix is realized through a simple solution casting technique that favors the nucleation and stabilization of 99.6% of the electroactive phase in PVDF (i.e., beta/gamma-phases). The enhancement of the output voltage (3.6 V) and current (2.4mA) of the NG based on a nonelectrically poled BNS containing PVDF composite film is achieved and demonstrated by simple repeated human finger imparting. The improvement of the output performance is influenced by the generation of the electroactive polar beta-phase in PVDF, due to the electrostatic interactions between the –CH2–/–CF2– dipoles of PVDF and the surface charge of the BNS. The NGs are able to charge up capacitors demonstrating that the power generation from such a hybrid device structure can be utilized for powering various portable devices. KW - Nanogenerators KW - energy harvesting KW - PVDF KW - bismuth oxide KW - Field-emission scanning electron microscopy (FESEM) KW - X-ray photoelectron spectroscopy (XPS) KW - X-ray diffraction (XRD) KW - Fourier Transform Infrared Spectroscopy (FTIR) Y1 - 2019 U6 - https://doi.org/10.1002/pc.24628 SN - 0272-8397 SN - 1548-0569 VL - 40 IS - S1 SP - E265 EP - E274 ER -