School Of Basic And Applied Sciences

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    Janus ?-PdXY (X/Y = S, Se, Te) materials with high anisotropic thermoelectric performance
    (Royal Society of Chemistry, 2023-02-21T00:00:00) Jakhar, Mukesh; Sharma, Raman; Kumar, Ashok
    Two-dimensional (2D) materials have garnered considerable attention as emerging thermoelectric (TE) materials owing to their unique density of states (DOS) near the Fermi level. We investigate the TE performance of Janus ?-PdXY (X/Y = S, Se, Te) monolayer materials as a function of carrier concentration and temperature in the mid-range from 300 to 800 K by combining density functional theory (DFT) and semi-classical Boltzmann transport theory. The phonon dispersion spectra and AIMD simulations confirm their thermal and dynamic stability. The transport calculation results reveal the highly anisotropic TE performance of both n and p-type Janus ?-PdXY monolayers. Meanwhile, the coexistence of low phonon group velocity and a converged scattering rate leads to a lower lattice thermal conductivity (Kl) of 0.80 W mK?1, 0.94 W mK?1, and 0.77 W mK?1 along the y-direction for these Janus materials, while the high TE power factor is attributed to the high Seebeck coefficient (S) and electrical conductivity, which are due to the degenerate top valence bands of these Janus monolayers. The combination of lower Kl and a high-power factor at 300 K (800 K) leads to an optimal figure of merit (ZT) of 0.68 (2.21), 0.86 (4.09) and 0.68 (3.63) for p-type Janus PdSSe, PdSeTe and PdSTe monolayers, respectively. To evaluate rational electron transport properties, the effects of acoustic phonon scattering (?ac), impurity scattering (?imp), and polarized phonon scattering (?polar) are included in the temperature-dependent electron relaxation time. These findings indicated that the Janus ?-PdXY monolayers are promising candidates for TE conversion devices. � 2023 The Royal Society of Chemistry.
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    Impact of shape (nanofiller vs. nanorod) of TiO2 nanoparticle on free-standing solid polymeric separator for energy storage/conversion devices
    (John Wiley and Sons Inc., 2019) Arya A.; Saykar N.G.; Sharma A.L.
    We report the investigation on examining the impact of nanofiller (NF)- versus nanorod (NR)-shaped titanium oxide (TiO2) nanoparticle on the structural, electrochemical, transport, thermal, and dielectric properties of the solid polymer electrolyte (SPE). Thin SPE films comprising of poly(ethylene oxide), sodium hexafluorophosphate, and dispersed with TiO2 NF, TiO2 NR (synthesized by hydrothermal route) has been prepared via solution cast technique. The shape of nanoparticle influences the morphological and structural properties as observed in field emission scanning electron microscope and X-ray diffraction analysis. The highest ionic conductivity was exhibited by the NR dispersed system and is higher than NF dispersed system for all recorded concentration consistently. It is attributed to the formation of the long-range conductive path with NR when compared with NF. In addition, the electrochemical stability window is much higher (~5 V) than the NF-doped system. Furthermore, the dielectric properties of SPE were investigated and fitted in the complete frequency window (1 Hz–1 MHz; T  = 40–100 °C @ 10 °C). It is observed that the NR dispersed system shows higher dielectric strength and low relaxation time with respect to NF dispersed system. The results suggest that the NR dispersed SPE possess enhanced properties and is more appropriate for an application in high energy density solid‐state Na ion batteries. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47361.