Sachindranath Das

Water Splitting by Using Electrochemical Properties of Material

The present era of ramping energy demands, its storage considerations coupled with environmental contentions being caused by the perishable conventional resources of energy, has set out a clear tone for the research community all across the globe to impart a motivated effort over it. If found, the genuine solution will go a long way to shift the paradigm from the current fossil-based economy to hydrogen-based one. The article at hand prima facie focuses on one of the most promising solutions to the aforementioned problem namely water splitting—more specifically so by harnessing the electrochemical properties of the material. While many options exist to furnish electricity for carrying out the water splitting but the cost compatibility with the other contemporary candidates poses the real bottleneck. The idea over here is to efficiently utilize the hitherto non-conventional methods of energy generation to efficiently and cost effectively achieves water splitting for the subsequent applications. As regards the current trends in water splitting, recent advances include carrying out water splitting by incorporating the visible portion alone from the available light. The resulting hydrogen may then subsequently be employed as a fuel input for different applications. Routes ranging from using advanced catalysis and even artificial photosynthesis are also being considered.

Frequency and temperature dependent dielectric properties of TiO2-V2O5 nanocomposites

In this manuscript, we have reported the crystal structure, dielectric response, and transport phenomenon of TiO2-V2O5 nanocomposites. The nanocomposites were synthesized using a sol-gel technique having different molar ratios of Ti:V (10:10, 10:15, and 10:20). The phase composition and the morphology have been studied using X-ray diffraction and field emission scanning electron microscope, respectively. The impedance spectroscopy studies of the three samples over a wide range of temperature (50 K–300 K) have been extensively described using the internal barrier layer capacitor model. It is based on the contribution of domain and domain boundary, relaxations of the materials, which are the main crucial factors for the enhancement of the dielectric response. The frequency dependent ac conductivity of the ceramics strongly obeys the well-known Jonschers power law, and it has been clearly explained using the theory of jump relaxation model. The temperature dependent bulk conductivity is fairly recognized to the variable-range hopping of localized polarons. The co-existence of mixed valence state of Ti ions (Ti3+ and Ti4+) in the sample significantly contributes to the change of dielectric property. The overall study of dielectric response explains that the dielectric constant and the dielectric loss are strongly dependent on temperature and frequency and decrease with an increase of frequency as well as temperature.

Organo-Lead Halide Perovskite Induced Electroactive β-Phase in Porous PVDF Films: An Excellent Material for Photoactive Piezoelectric Energy Harvester and Photodetector

Methylammonium lead iodide (CH3NH3PbI3) (MAPI)-embedded β-phase comprising porous poly(vinylidene fluoride) (PVDF) composite (MPC) films turns to an excellent material for energy harvester and photodetector (PD). MAPI enables to nucleate up to ∼91% of electroactive phase in PVDF to make it suitable for piezoelectric-based mechanical energy harvesters (PEHs), sensors, and actuators. The piezoelectric energy generation from PEH made with MPC film has been demonstrated under a simple human finger touch motion. In addition, the feasibility of photosensitive properties of MPC films are manifested under the illumination of nonmonochromatic light, which also promises the application as organic photodetectors. Furthermore, fast rising time and instant increase in the current under light illumination have been observed in an MPC-based photodetector (PD), which indicates of its potential utility in efficient photoactive device. Owing to the photoresponsive and electroactive nature of MPC films, a new class of stand-alone self-powered flexible photoactive piezoelectric energy harvester (PPEH) has been fabricated. The simultaneous mechanical energy-harvesting and visible light detection capability of the PPEH is promising in piezo-phototronics technology.

Dielectric relaxation and Ac conductivity of perovskites CH3NH3PbX3 (X = Br, I)

ABSTRACT MAPbX3 (MA = CH3NH3, X = Br, I) are synthesized by the chemical route. The Rietveld refinement of the room temperature X-ray diffraction pattern of the materials shows that MAPbBr3 is crystallized in the cubic Pm3m crystal symmetry whereas MAPbI3 crystallizes in the tetragonal phase with space group I4/mcm. The dielectric relaxation of MAPbX3 has been studied in the frequency range from 42 Hz to 0.2 MHz in the electric modulus formalism. The relaxation time is determined by the reciprocal of the frequency where the maximum of the imaginary part of the electric modulus is centred. The relaxation mechanism of the samples is investigated by the Cole-Cole model. The complex impedance plane plots are analyzed by an electrical equivalent circuit consisting of a resistance and a capacitance. The frequency dependent conductivity spectra follow the power law.