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There is an urgent demand in the industry for the development of compact, flexible, and sustainable power sources for self-powered internet of things (IoT) micro/nano devices. One of the most promising routes is to harness environmental energy through piezoelectric nanogenerators (PNGs). A novel, self-assembled, highly porous perovskite/polymer (polyvinylidene fluoride (PVDF) in this case) composite film was developed for fabricating high-performance piezoelectric nanogenerators (PNGs). The macroscopic porous structure can significantly enlarge the bulk strain of the piezoelectric composite film, which leads to a ≈5-fold enhancement in the strain-induced piezo potential. In addition, the novel hybrid halide perovskites (HHP)–formamidinium lead bromine iodine (FAPbBr2I) material can improve the conductivity of the final composite film due to its enhanced permittivity, providing a ≈15-fold amplification of the output current. Using these highly-efficient perovskite/polymer PNGs (P-PNGs), a peak output power density of 10 μW cm−2 (across a resistance of 7 MΩ) was obtained to run a self-powered integrated wireless electronic node (SIWEN). The P-PNG application was then extended to real-life scenarios including wireless data communication between the nanogenerators and personal electronics, efficient energy harvesting from automobile vibrations and also from biomechanical motion. This P-PNG based on a low-temperature full-solution synthesis approach, may initiate a paradigm shift by opening the realms of flexible PNGs as sustainable power sources. [ABSTRACT FROM AUTHOR]

In the present study, a novel electrically conductive polypyrrole–titanium(iv)sulphosalicylophosphate (PPy–TSCP) cation exchange nanocomposite was synthesized by an in situ chemical oxidative polymerization of pyrrole in the presence of titanium(iv)sulphosalicylophosphate (TSCP). The PPy–TSCP cation exchange nanocomposite was characterized by various instrumentation techniques such as FTIR, FE-SEM, XRD, TGA, DTA, DTG and EDXA. The composite exhibited good ion-exchange capacity (IEC) (2.10 meq g−1) as well as electrical conductivity (0.756 S cm−1) and isothermal stability in terms of DC electrical conductivity retention under ambient conditions up to 100 °C. The PPy–TSCP cation exchange nanocomposite based sensor was fabricated for the detection of acetaldehyde vapours, and it was found that the resistivity of the nanocomposite increases on exposure to a high concentration of acetaldehyde vapors at room temperature (25 °C). The rate of reaction for acetaldehyde vapour sensing on PPy–TSCP was observed to be first order. [ABSTRACT FROM AUTHOR]

Electrical stimulation of nervous tissue is used clinically for the treatment of multiple neurological disorders and experimentally for basic research. With the increase of optical probes to record neuronal activity, simple and user-friendly methods are desired to stimulate neurons and their subcellular compartments for biological experimentation. Here we describe the novel integration of liquid metal electrodes with microfluidic culture platforms to accomplish this goal. We integrated electrode and cell channels into a single poly(dimethylsiloxane) (PDMS) chip, eliminating entirely the need to align electrodes with microchannels. We designed the electrode channels such that the metal can be injected by hand and when the device is non-covalently bound to glass. We demonstrated the biocompatibility of the electrodes for long-term cultures (12 days) using hippocampal neurons. We demonstrated the use of these electrodes to depolarize neurons and recorded neuronal activity using the calcium indicator dye, Fluo-4. We established optimal stimulation parameters that induce neuronal spiking without inducing damage. We showed that the liquid metal electrode evoked larger calcium responses in somata than bath electrodes using the same stimulus parameters. Lastly we demonstrated the use of these liquid metal electrodes to target and depolarize axons. In summary, the integration of liquid metal electrodes with neuronal culture platforms provides a user-friendly and targeted method to stimulate neurons and their subcellular compartments, thus providing a novel tool for future biological investigations.