Sandeep Patnaik

Aqueous based reflux method for green synthesis of nanostructures: Application in CZTS synthesis

Graphical abstract

Impedance spectroscopy studies of surface engineered TiO2 nanoparticles using slurry technique

Dielectric analysis of nanometre range size ceramic particles like TiO2 is very important in the understanding of the performance and design of their polymer nanocomposites for energy storage and other applications. In recent times, impedance spectroscopy is shown to be a very powerful tool to investigate the dielectric characteristics of not only sintered and/or pelleted ceramic materials but also particulates/powders (both micron-sized and nano-sized) using the slurry technique. In the present work, impedance spectroscopy employing slurry methodology was extended to study the influence of various chemical groups on the nanoTiO2 surface on the electrical resistivity and the dielectric permittivity of nanoparticles. In this regard, different organophosphate ligands with linear, aromatic and extended aromatic nature of organic groups were employed to remediate the surface effects of nanoTiO2. It was observed that the type of chemical nature of surface engineered nanoparticles’ surface played significant role in controlling the surface electrical resistivity of nanoparticles. Surface passivated nanoTiO2 yielded dielectric permittivity of about 70–80, respectively.

Enhanced dissolution characteristics of piroxicam–Soluplus® nanosuspensions

ABSTRACT In the present study, we have prepared nanosuspensions of piroxicam using Soluplus® as the matrix using aqueous-based conventional ball milling. The comparative physico-chemical characteristics were assessed using PXRD (powder X-ray diffraction), DSC (differential scanning calorimetry), FESEM (field emission scanning electron microscopy) and FTIR (Fourier transform infrared spectroscopy) analysis, indicating the nanoformulations displayed lower crystallinity with no chemical interactions between the drug and polymer molecules. The cytotoxicity of the formulations was established from MTT assay performed on Caco-2 cell lines. The release rate of piroxicam from various ratios of drug/polymer nanoparticles was investigated using a USP paddle apparatus. The nanoformulations exhibited higher release of the drug in comparison with the pure drug. The enhanced dissolution characteristics of the drug in the nanoformulations could possibly increase the anti-inflammatory effects of the drug owing to superior bioavailability characteristics.

Cu2ZnSnS4 synthesized through a low-cost reflux method

Abstract The chalcopyrite semiconductors belonging to the I2-II-IV-VI4 class are emerging as promising absorber materials for photovoltaic applications. Among them, Cu2ZnSnS4 (CZTS) has been gaining importance due to its high absorption coefficient and optimum band-gap. To make CZTS an economically viable alternative, in this study, the CZTS powder has been synthesized via a low-cost, environment-friendly reflux method. In the current method, the salts of the respective metals were taken as initial precursors, and thiourea was used as a precursor for sulfur. The stoichiometric amounts of the precursors were taken in distilled water and the solution was refluxed for 8 h. The products were filtered and washed with distilled water and ethanol consecutively. Phase identification was done using powder X-ray diffraction (given by the reference pattern JCPDS card no. #00-026-0575) and Raman spectroscopy analysis (corresponding Raman shifts for CZTS: 288 and 338 cm-1). The band gap of the compound was calculated from the UV-visible spectroscopy and found to be 1.4 eV.