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Subject: search.filters.subject.Perovskites

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    WO3:AgInS2 quantum dot electron transport layers in enhanced perovskite solar cells
    (2023-04-14)
    Seriwattanachai, Chaowaphat
    ;
    Kaewprajak, Anusit
    ;
    Sukgorn, Nuttaya
    ;
    Kumnorkaew, Pisist
    ;
    Nukeaw, Jiti
    The development of the electron transport layers (ETL) was crucially important for the improvement of charge extraction and transportation in perovskite solar cells (PSCs). Here, dual electron transport layers of TiO<inf>2</inf> and WO<inf>3</inf> mixed with different sizes of AgInS<inf>2</inf> quantum dots (TiO<inf>2</inf>/WO<inf>3</inf>:AgInS<inf>2</inf> QDs) were fabricated for planar perovskite solar cells. The peak intensity of the photoluminescence (PL) of the synthesized AgInS<inf>2</inf> QDs were redshifted from 554 to 655 nm with an increased radius of AgInS<inf>2</inf> QDs from 3.82 ± 0.52 to 7.78 ± 1.37 nm. The PL intensity of the perovskite film on TiO<inf>2</inf>/WO<inf>3</inf>:AgInS<inf>2</inf> QDs was quenched by the addition of AgInS<inf>2</inf> QDs. The improved device stability was probably caused by the WO<inf>3</inf>:AgInS<inf>2</inf> QDs layer protecting the interface of perovskite layers from direct contact with TiO<inf>2</inf> to prevent UV decomposing. Therefore, the TiO<inf>2</inf>/WO<inf>3</inf>:AgInS<inf>2</inf> QDs as electron transport layers promoted the perovskite solar cell performance and enhanced the long-term stability. Graphical abstract: [Figure not available: see fulltext.].
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    Effect of sr substitution on structural, ferroelectric and magnetic properties of la1-xsrxfeo3 perovskite oxides
    (2020-01-01)
    Kaewpanha, Malinee
    ;
    Nunocha, Pornnipa
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    Bongkarn, Theerachai
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    Eiad-Ua, Apiluck
    ;
    Suriwong, Tawat
    Effect of Sr substitution on structural, magnetic and electrical properties of LaFeO<inf>3</inf> perovskite oxides has been studied. Using the selected Sr doping content (x) from 0.0 to 1.0, perovskite La<inf>1-x</inf>Sr<inf>x</inf>FeO<inf>3</inf> nanopowder was synthesized by sol-gel auto-combustion method, followed by calcination at 900 °C for 2 h. The synthesized powder was pressed into disks at room temperature and then the disk samples were sintered at 1200 °C for 12 h to obtain a single-phase compound formation and uniaxial compaction. The influence of Sr doping on the phase formation, morphology, ferroelectric and magnetic properties was investigated. The phase formation of the sample changes from orthorhombic at low Sr doping through rhombohedral to cubic for Sr-rich sample as the stoichiometry approached SrFeO<inf>3</inf>. The grains of La<inf>1-x</inf>Sr<inf>x</inf>FeO<inf>3</inf> ceramics revealed an irregular polyhedron shape. SEM-EDS mapping analysis also exhibited the uniform distribution of all elements. The direct energy gap (E<inf>g</inf>) was found to decrease with increasing amounts of Sr doping. Moreover, the La<inf>0.6</inf>Sr<inf>0.4</inf>FeO<inf>3</inf> ceramic exhibited ferromagnetic behavior with saturated magnetization (M<inf>s</inf>) of 0.305 emu/g at room temperature.
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    Effect of platinum substitution on the microstructures and dielectric relaxation of CaCu3Ti4O12 ceramics
    (2013-10-29)
    Makcharoen, Worawut
    The CaCu<inf>3</inf>Ti<inf>4</inf>O<inf>12</inf> (CCTO) has the advantage for the various applications especially for capacitive elements in microelectronic devices over the ferroelectric materials including BaTiO<inf>3</inf>. CCTO is a ceramic compound with a high dielectric constant but it has a high loss tangent at room temperature. In this work, the Influences of PtO<inf>2</inf> doping on the dielectric properties of CaCu<inf>3</inf>Ti<inf>4</inf>O<inf>12</inf> (CCTO) ceramics were investigate. The ceramics CCTO and PtO<inf>2</inf> doping CCTO were studied by Xray diffraction, scanning electron microscopy. The dielectric properties have been measured as a function of temperature and frequency range 0.1 - 500 kHz. The XRD shows the CCTO structure does not changes after doping with platinum. The results show that PtO<inf>2</inf> doped can reduce the mean grain sizes of CCTO, but the dielectric constant still remained a height. The samples of 2.0 mol% Pt-doped have exhibited high dielectric constant of about 22,000 and the loss tangent about 0.7 at room temperature and frequency at 10 kHz. The reduced of the loss tangent could be interpreted with the internal barrier layer capacitor model (IBLC) © (2013) Trans Tech Publications, Switzerland.
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    Synthesis and dielectric and ferroelectric properties of ceramics in (1 - X)Pb(Zr1/2Ti1/2)O3-(x)Pb(Co 1/3Nb2/3)O3 system
    (2008-02-15)
    Prasatkhetragarn, Anurak
    ;
    Vittayakorn, Naratip
    ;
    Ananta, Supon
    ;
    Yimnirun, Rattikorn
    ;
    Cann, David P.
    Ceramics in a PZT-PCN system with the formula (1 - x)Pb(Zr <inf>1/2</inf>Ti<inf>1/2</inf>)O<inf>3</inf>-(x)Pb(Co<inf>1/3</inf>Nb <inf>2/3</inf>)O<inf>3</inf>, where x = 0.1-0.5, were prepared using a solid-state mixed-oxide technique (the columbite-wolframite precursor method). The phase formation behavior and microstructure were studied using X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM), respectively. The dielectric and ferroelectric properties of the compounds were studied and discussed. Phase-pure perovskites of PZT-PCN ceramics were obtained over a wide compositional range. In addition, the XRD, dielectric, and ferroelectric properties confirmed that the morphotropic phase boundary (MPB) composition between the tetragonal and pseudo cubic phases of this system lied between 0.2 ≤ × ≤ 0.3. © 2008 The Japan Society of Applied Physics.
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    Influence of fabrication processing on perovskite phase formation of KNN-BZT
    (2008-01-01)
    Sutapun, M.
    ;
    Muanghlua, R.
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    Huang, C. C.
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    Cann, D. P.
    ;
    Vittayakorn, W. C.
    The binary system of (1-x)(K<inf>1/2</inf>Na<inf>1/2</inf>)NbO <inf>3</inf>-xBi(Zni/2Ti<inf>1/2</inf>)O<inf>3</inf>; x = 0.0-0.30 ceramics was fabricated by conventionally mixed oxide and two-stage mixed oxide methods. Phase development of calcined powders and the crystal structure of sintered ceramics were analyzed by X-ray diffraction (XRD). The microstructure analyses were undertaken by scanning electron microscopy (SEM). In the conventional method, the perovskite phases were obtained for compositions containing only 10 mol % KNN. For compositions above this amount, a complex mixture of phases was observed. However, the complete solid solution of perovskite phase, prepared by two-stage mixed oxide, was retained up to 20 mole % BZT content. The experiments in this study suggest that the two-stage mixed oxide method helps to stabilize the perovskite phase better, when compared with the conventional method. © 2008 Trans Tech Publications, Switzerland.