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 - TY - GEN A1 - Kot, Małgorzata A1 - Henkel, Karsten A1 - Naumann, Franziska A1 - Gargouri, Hassan A1 - Tarnawska, Lidia Lupina A1 - Wilker, Viola A1 - Kus, Peter A1 - Pożarowska, Emilia A1 - Garain, Samiran A1 - Rouissi, Zied A1 - Schmeißer, Dieter T1 - Comparison of plasma-enhanced atomic layer deposition AlN films prepared with different plasma sources T2 - Journal of Vacuum Science and Technology A N2 - A comparative study of thin aluminum nitride (AlN) films deposited by plasma-enhanced atomic layer deposition in the SENTECH SI ALD LL system applying either a direct inductively coupled plasma (ICP) or an indirect capacitively coupled plasma (CCP) source is presented. The films prepared with the ICP source (based on a planar triple spiral antenna) exhibit improved properties concerning the growth rate per cycle, total cycle duration, homogeneity, refractive index, fixed and mobile electrical charges, and residual oxygen content compared to the CCP source, where the comparison is based on the applied plasma power of 200 W. The increase of the plasma power to 600 W in the ICP process significantly reduces the residual oxygen content and enhances the electrical breakdown field. The AlN layers grown under these conditions, with a growth rate per cycle of 1.54 Å/cycle, contain residual oxygen and carbon concentrations of about 10% and 4%, respectively, and possess a refractive index of 2.07 (at 632.8 nm). KW - Plamsa-enhanced atomic layer deposition (PEALD) KW - inductively coupled KW - capacitively coupled KW - plamsa source KW - ellipsometry KW - X-ray photoelectron spectroscopy (XPS) KW - X-ray diffraction (XRD) KW - Field emission scanning electron microscopy (FESEM) KW - capacitance-voltage (CV) KW - atomic force microscopy Y1 - 2019 U6 - https://doi.org/10.1116/1.5079628 SN - 0734-2101 SN - 1520-8559 VL - 37 IS - 2 ER - TY - GEN A1 - Roy, Krittish A1 - Ghosh, Sujoy Kumar A1 - Sultana, Ayesha A1 - Garain, Samiran A1 - Xie, Mengying A1 - Bowen, Christopher Rhys A1 - Henkel, Karsten A1 - Schmeißer, Dieter A1 - Mandal, Dipankar T1 - A Self-Powered Wearable Pressure Sensor and Pyroelectric Breathing Sensor Based on GO Interfaced PVDF Nanofibers T2 - ACS Applied Nano Materials N2 - This paper reports a self-powered,flexible, piezo- and pyro-electric hybrid nanogenerator (NG) device that can be fixed on different locations of human skin for detecting static and dynamic pressure variations and can also monitor temperature fluctuations during the respiration process. An efficient and cost-effective fabrication strategy has been developed to create electrospun poly(vinylidene fluoride) (PVDF)/graphene oxide (GO) nanofibers, which are used to create a highly sensitive wearable pressure sensor and pyroelectric breathing sensor. The sensor can accurately and rapidly detect pressures as low as 10 Pa with a high sensitivity (4.3 V/kPa), a key performance indicator for wearable sensors. Importantly, the sensor exhibits a high sensitivity to bending and stretching by finger, wrist, and elbow. The pressure sensor is also highly sensitive to vocal vibrations when attached to the human throat. The device can generate a maximum output power density of∼6.2 mW/m2 when subjected to a compressive stress, which enhances its range of applications. Moreover, it is demonstrated that doping with GO improves the pyroelectric energy harvesting and sensing performance of the device under repeated temperature fluctuations. The PVDF/GO-based nanogenerator has a maximum pyroelectric output power density of∼1.2 nW/m2 and can sense temperature changes during respiration, which makes it promising as a pyroelectric breathing sensor. It is demonstrated that processing of the PVDF-GO self-powered multifunctional pressure and pyroelectric breathing sensor can be up-scaled for fabricating compact and high-performance electronic skins for application in health monitoring, motion detection, and portable electronics. KW - piezo- and pyro-electric hybrid nanogenerator KW - poly(vinylidenefluoride) (PVDF)/graphene oxide (GO) nanofibers KW - wearable pressure sensor KW - breathing sensor Y1 - 2019 U6 - https://doi.org/10.1021/acsanm.9b00033 SN - 2574-0970 VL - 2 IS - 4 SP - 2013 EP - 2025 ER -