Single crystals of potassium acid phthalate (KAP) and amino acid (DL-Alanine, L-Methionine) doped KAP were grown from aqueous solutions by slow cooling method. The grown crystals were characterized using powder X Ray diffraction (XRD) and Fourier Transform Infrared (FTIR) analysis. The thermal stability of KAP in the presence of dopants was analysed using Thermogravimetric and Differential Scanning caloriemetric (TGA/ DSC) studies and the maximum temperature for non linear optical application of this compound in the presence of dopants was found out. The transmittance of KAP was found to increase in the presence of dopants. Etch pits were observed for all the crystals using different etchants. Vickers microhardness tests were performed to study the mechanical stability of the crystals. The hardness of DLalanine doped KAP is more than that of L-alanine doped KAP crystal. The dielectric constant and loss were determined as a function of temperature. Frequency response of the dielectric constant and dielectric loss factor have been studied over the frequency range of 50Hz -5MHz. Second harmonic generation (SHG) was confirmed in all the crystals using the Kurtz and Perry powder technique.

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Zinc–tin–vanadium oxide (ZTV) nanocomposite room temperature ethanol sensor (98.96% for 300 ppm) with fast adsorption (32 s) and desorption (6 s) rate is reported for first time and the mechanism is elucidated based on its structure and morphology.

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Mesoporous zinc oxide nanostructures are successfully synthesized via the sol-gel route by using a rice husk as the template for ethanol sensing at room temperature. The structure and morphology of the nanostructures are characterized by x-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption-desorption analyses. The mechanism for the growth of zinc oxide nanostructures over the biotemplate is proposed. SEM and TEM observations also reveal the formation of spherical zinc oxide nanoparticles over the interwoven fibrous network. Multiple sized pores having pore diameter ranging from 10-40 nm is also evidenced from the pore size distribution plot. The larger surface area and porous nature of the material lead to high sensitivity (40.93% for 300 ppm of ethanol), quick response (42 s) and recovery (40 s) towards ethanol at 300 K. The porous nature of the interwoven fibre-like network affords mass transportation of ethanol vapor, which results in faster surface accessibility, and hence it acts as a potential candidate for ethanol sensing at room temperature.

Zinc oxide (ZnO) / Tin oxide (SnO 2 ) / Zinc stannate (Zn 2 SnO 4 ) nanocomposite is prepared via hydrothermal route followed by calcination. The nanocomposite is characterized by X-ray powder diffraction, Fourier Transform Infrared spectroscopy and UV spectroscopy techniques. The nanocomposite's morphology and the elemental composition is recorded using field emission scanning electron microscopy and energy dispersive X-ray spectroscopy analysis. The nanorods dispersed in the matrix of nanoparticles increases the surface active sites for gas adsorption and this material would be explored as a potential candidate for gas sensing applications at room temperature with quick response and recovery in the near future.

Zinc oxide (ZnO) and aluminum (Al) doped ZnO nanostructures with and without surfactant have been successfully prepared via sol-gel route. The effect of the surfactant glyoxalic acid and various concentration of Al on the structural property of ZnO was analyzed by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). The morphology of the samples was recorded using field emission scanning electron microscopy. The uniform distribution of ZnO nanostructures with hexagonal facets is facilitated by the surfactant and the grain growth is further inhibited by the increase in concentration of Al. The ethanol (0–300[Formula: see text]ppm) sensing characteristics of the as-prepared samples were systematically investigated at room temperature. Surfactant-assisted ZnO/Al:ZnO nanostructures show higher sensitivity of 94% at room temperature than ZnO/Al:ZnO nanostructures without surfactant. Faster response at 68[Formula: see text]s and recovery at 50[Formula: see text]s is also achieved by the samples. The surfactant-assisted ZnO nanostructures exhibit sharp selective detection towards ethanol when compared to the samples without surfactant. The enhanced ethanol sensing property may be ascribed to the larger surface area which is due to uniform and smaller crystallite size of the surfactant-assisted sample.