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    Strain engineering and thermal conductivity of a penta-BCN monolayer: A computational study
    (2021-09-01)
    Dabsamut, Klichchupong
    ;
    Thanasarnsurapong, Thanasee
    ;
    Maluangnont, Tosapol
    ;
    T-Thienprasert, Jiraroj
    ;
    Jungthawan, Sirichok
    Two-dimensional (2D) pentagonal nanostructures have been caught research attention down to their electronic, optical, mechanical and thermal transport properties. Among them, the newly proposed ternary penta-BCN monolayer shows a great potential for piezoelectric materials according to intrinsic piezoelectricity and spontaneous polarization. Nevertheless, the effect of strain toward these properties of the penta-BCN has not been elucidated. In this study, using density-functional theory with the Perdew-Burke-Ernzerhof (PBE) functional, we have investigated the impact of a uniform biaxial strain on the electronic structure and the thermal conductivity of the semiconducting penta-BCN single sheet. The strain-free penta-BCN monolayer is mechanically and dynamically stable with an indirect band gap of 1.70 eV. The sheet is rather soft as judged from the low in-plane Young's moduli. The pentagonal structure is preserved up to the yielding point of 18.4%, beyond this point the irreversible transition into the dynamically unstable, honeycomb-like system is observed. In contrast, the penta-BCN has dynamically instability under the compressive strain as small as -4%. The PBE band gap of the penta-BCN monolayer could be tuned within a range of 1.36-1.70 eV, falling into the infrared spectrum. The calculated lattice thermal conductivity of penta-BCN is around 97 W m-1 K-1 at temperature of 300 K, and decreases with increasing temperature.
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    High-Performance Hybridized Composited-Based Piezoelectric and Triboelectric Nanogenerators Based on BaTiO3/PDMS Composite Film Modified with Ti0.8O2 Nanosheets and Silver Nanopowders Cofillers
    (2019-05-28)
    Sriphan, Saichon
    ;
    Charoonsuk, Thitirat
    ;
    Maluangnont, Tosapol
    ;
    Vittayakorn, Naratip
    In order to commercialize the rapidly developing technology of energy harvesters, the following devices need to be developed further for enhancing output performance, flexibility, scalability, facile fabrication, and cheaper price. The composite-based triboelectric nanogenerator (CTENG), which contains the above properties, is a promising technology that has attracted special interest for a decade. Focus has been placed on the hybrid concept between the composite-based piezoelectric nanogenerator (CPENG) and CTENG in order to enhance CTENG efficiency. This study presented a high-performance hybridized CPENG and CTENG device, which operated from the composite film of Ti<inf>0.8</inf>O<inf>2</inf> nanosheets (Ti NSs)/silver nanoparticles (Ag NPs) co-doped BaTiO<inf>3</inf> nanopowders (BT NPOs) inside the polydimethylsiloxane (PDMS) host. The 0.3 vol % of Ti NSs and 1.5 vol % of Ag NPs exhibited the optimum harvesting performance in all compositions, with an output voltage and current density reaching approximately 150 V and 0.32 μA/cm<sup>2</sup>, respectively. Their harvesting performance was approximately 60 and 32 times higher than that of the CPENG constructed from pure PDMS. In addition, practical demonstration of the proposed device was investigated. The hybridized CPENG and CTENG device could operate in a long-term cyclic operation, charge the capacitor for storing energy, and also drive LEDs to brighten. This work suggested facile device fabrication and made a guideline to develop high-performance nanogenerators, which is crucial for device development and practical usage in the future.