KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Access type: UnknownAuthor: search.filters.author.Jayasankar, Chalicheemalapalli Kulala

Search Results

Now showing 1 - 3 of 3
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Turning the Near-Infrared Shielding Performance of Erbium/Antimony-Codoped Tin Oxide Nanomaterials Derived via a Sonochemically Assisted Method
    (2026-04-07)
    Kansaard, Thanaphon
    ;
    Noinonmueng, Tanisara
    ;
    Jayasankar, Chalicheemalapalli Kulala
    ;
    Mekprasart, Wanichaya
    ;
    Boonyarattanakalin, Kanokthip
    Energy consumption is one of the most important concerning issues of environmental problems especially the global warming phenomenon, with energy usage being the main cause. To reduce the energy used for cooling systems, development of material for smart buildings for near-infrared (NIR) protection is a challenge of material society. Metal oxides including tin oxide (SnO2) with an antimony (Sb) dopant are a candidate owing to their NIR shielding property. However, the upgrading of NIR absorption performance with rare-earth doping due to the specific property of rare-earth elements especially erbium (Er) shows strong absorption of the near-infrared region. This article synthesized Er/Sb-codoped SnO2 nanoparticles by sonochemical and thermal treatment processes at various Er dopant concentrations with a Sb dopant concentration stabilized at 5%. Crystallinity and morphology exhibited the tetragonal phase of SnO2 with a sphere-like nanostructure with an approximately average size of 10 nm. X-ray photoelectron spectroscopy was used to evaluate the chemical oxidation state of all elements, which verified the Er3+ and Sb5+ oxidation states of dopant ions, and oxygen vacancy observation led to the NIR absorption improvement.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Er-Doped BiVO4/BiFeO3 Nanocomposites Synthesized via Sonochemical Process and Their Piezo-Photocatalytic Application
    (2024-06-01)
    Kansaard, Thanaphon
    ;
    Songpanit, Maneerat
    ;
    Noonuruk, Russameeruk
    ;
    Wattanawikkam, Chakkaphan
    ;
    Mekprasart, Wanichaya
    In this work, Er-doped BiVO<inf>4</inf>/BiFeO<inf>3</inf> composites are prepared using the sonochemical process with a difference of rare earth loading compositions. The crystallinity and chemical and morphological structure of as-synthesized samples were investigated via X-ray diffraction, Raman scattering, and electron microscopy, respectively. The diffuse reflectance technique was used to extract the optical property and calculate the optical band gap of the composite sample. The piezo-photocatalytic performance was evaluated according to the decomposition of a Rhodamine B organic compound. The decomposition of the organic compound was achieved under ultrasonic bath irradiation combined with light exposure. The Er-doped BiVO<inf>4</inf>/BiFeO<inf>3</inf> composite heterojunction material exhibited significant enhancement of the piezo-photocatalytic activity under both ultrasonic and light irradiation due to the improvement in charge generation and separation. The result indicates that Er dopant strongly affects the phase transformation, change in morphology, and alternation in optical band gap of the BiVO<inf>4</inf> matrix. The incorporation of BiFeO<inf>3</inf> in the composite form with BiVO<inf>4</inf> doped with 1%Er can improve the photocatalytic performance of BiVO<inf>4</inf> via piezo-induced charge separation and charge recombination retardment.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    A homogeneous composite approach for improved thermoelectric performance: Repressing lattice thermal conductivity in substoichiometric WO2.90 and WO2.72
    (2023-12-15)
    Tran, Nhat Quang Minh
    ;
    Pham, Anh Tuan Thanh
    ;
    Nguyen, Cuong Chi
    ;
    Tran, Tien Thuy Nguyen
    ;
    Lai, Hoa Thi
    Nanostructured phonon-glass thermoelectric materials are highly sought after for heat waste recovery applications. This work introduces a novel phonon-glass multi-phase ceramic material synthesized from sintered mixtures of two sub-stoichiometric tungsten oxides, WO<inf>2.90</inf> and WO<inf>2.72</inf>. Notable measurements were recorded for our sample, denoted as 0.1WO<inf>2.72</inf>/0.9WO<inf>2.90</inf>, at 800 °C, with S<sup>2</sup>σ = 0.51 ± 0.03 mWm<sup>−1</sup>K<sup>−2</sup>, representing a tenfold increase compared to the base materials. The lattice thermal conductivity, already displaying phonon-glass characteristics, is further suppressed by the addition of the secondary WO<inf>2.72</inf> pentacolumn phase, reaching its lowest value at 0.54 ± 0.25 Wm<sup>−1</sup>K<sup>−1</sup>. As a result, the ZT value is enhanced to twice the intrinsic value of the pristine phase. This study demonstrates a novel strategy for improving the thermoelectric performance of oxide-based materials by leveraging a synergistic relationship among several key factors, including phonon-glass nanostructures, tunable electrical properties, and the reduction of lattice thermal conductivity within a homogeneous composite system.