School Of Basic And Applied Sciences

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    Probing the impact of bismuth-titanate based nanocomposite on the dielectric and electro-optical features of a nematic liquid crystal material
    (Elsevier B.V., 2021-12-22T00:00:00) Varshney, Depanshu; Anu; Prakash, Jai; Pratap Singh, Vinay; Yadav, Kamlesh; Singh, Gautam
    We report here the concentration and temperature dependent optical, electro-optical and dielectric studies on bismuth titanate (Bi2Ti2O7/Bi4Ti3O12) nanocomposite (BT2/BT4 NC, ?42 nm) doped nematic liquid crystal (NLC, 5CB) mixtures using optical polarising microscope and dielectric spectroscopic techniques. The optical textures confirm the uniform dispersion and miscibility of NCs in 5CB for all concentrations (i.e. 0.1, 0.25, 0.5, 1 and 2 wt%) and mixtures appear to be almost agglomeration free. The dielectric studies demonstrate the maximum changes in the dielectric parameters (dielectric permittivity, dielectric loss, loss factor and dielectric anisotropy) of 5CB sample for the 0.1 wt% mixture. Interestingly, the dielectric anisotropy of 5CB in 0.1 wt% mixture is increased by ? 11%. However, the dielectric memory effect (bias voltage ON-OFF) is observed maximum in the case of 1 wt% mixture. Similarly, the optical memory examined by bias voltage dependent (ON-OFF) optical textures is also significantly enhanced for 1 wt% mixture. The significant changes observed in dielectric properties of 5CB sample could be due to plausible interaction among NLC molecules and ionic impurities with BT2/BT4 NCs. Moreover, the enhanced volatile memory in BT2/BT4 NC-NLC mixture could be attributed to the dipole�dipole coupling between individual permanent dipole moment of anisotropic NLC molecules with the dipole moments generated by the ionic impurities agglomerated on the surface of high dielectric BT2/BT4 NCs. We strongly believe that such NCs-NLC mixtures would be certainly useful in the advancement of wearable devices (such as smart plenoptic cameras, watches etc.) and smart switchable windows. � 2021 Elsevier B.V.
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    Facile synthesis of Bi2WO6/rGO nanocomposites for photocatalytic and solar cell applications
    (Elsevier Ltd, 2021-02-22T00:00:00) Shad, Naveed Akhtar; Sajid, Muhammad Munir; Afzal, Amir Muhammad; Amin, Nasir; Javed, Yasir; Hassan, Safia; Imran, Zahid; Razaq, Aamir; Yousaf, Muhammad Imran; Munawar, Anam; Sharma, Surender Kumar
    Manipulation of materials at nanoscale provides many new and enhanced properties to be utilized for multifaceted applications, which was not possible before. In this study, we fabricated Bi2WO6/rGO composites using hydrothermal method. The obtained composites were then examined using different analytical techniques such as XRD, SEM, TEM, FTIR, XPS, BET, and AFM. Their catalytic properties were assayed by carrying out the degradation of organic dye Rhodamine B (RhB) and employed as a hole transport layer (HTL) in the perovskite solar cells. The fabricated nanocomposites were able to degrade 98% of dye solution within 4 h. The improved photocatalysis is attributed to a large surface area ~86.06 m2/g with pore size 7.812 nm and enhanced separation of electron-hole pair charges due to rGO sheets. The open-circuit voltage was increased up to 0.94 V when composite materials were used as HTL. The power conversion efficiency (PCE) of the device was enhanced to 11% because of the improvement in the interface quality between HTL and the perovskite layer. It is conceived that the fabricated nanomaterial may show excellent potential in smart solar cell applications. � 2021 Elsevier Ltd and Techna Group S.r.l.