Synthesis Process of BaMgAl[sub 10]O[sub 17]:Eu[sup 2+] from Sol-Gel-Derived Eu[sup 2+]-Activated Fluoride Precursors without H[sub 2] Annealing Treatments

Fujihara, Shinobu; Kishiki, Yoko; Kimura, Takeshi

doi:10.1149/1.1785794

Cited by 8 publications

(8 citation statements)

References 27 publications

(24 reference statements)

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“…Moreover, the spectral structure is quite similar to that of BaMgAl 10 O 17 :Eu 2+ which is recognized as one of the most efficient blue phosphors for practical use. 30 The chromaticity ͑x,y͒ coordinates in the Commission Internationale d'Eclairage ͑CIE͒ diagram were determined to be ͑0.156, 0.164͒, ͑0.156, 0.153͒, and ͑0.156, 0.147͒ for the emission centered at 456, 454, and 451 nm, respectively, which were located in the center of the blue region. As to the mechanism of the blue PL, we consider that oxygen vacancies ͑especially V O • defects͒ play a key role, like the green PL in ZnO.…”

Section: J284mentioning

confidence: 99%

Blue Luminescence of MgZnO and CdZnO Films Deposited at Low Temperatures

Ogawa

Fujihara

2007

J. Electrochem. Soc.

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Blue photoluminescence was successfully generated from zinc oxide by doping magnesium or cadmium. MgZnO and CdZnO films were deposited on glass substrates by a spin-on/pyrolysis with low heating temperatures ͑600-700°C͒ in H 2 /N 2 and air, respectively. Structural analysis revealed that all the films were crystallized in the wurtzite-type structure. The c-axis length of ZnO was changed by the doping, indicating that Mg and Cd could be incorporated into the ZnO lattice through the present synthetic method. This incorporation was also supported by the occurrence of blue-and redshift of the optical bandgap by Mg and Cd doping, respectively. In case of MgZnO, the bandgap was increased up to 3.67 eV, resulting in a deep-level blue luminescence centered at 2.75 eV ͑corresponding to 451 nm͒ upon irradiation with UV light. This might be a color-tuning of the well-known green emissions from oxygen defect centers. In photoluminescence spectra of CdZnO, blue emission bands centered at 437 nm appeared by the Cd doping, possibly arising from the increased emissive defect centers related to interstitial zinc atoms. We could therefore produce two kinds of blue emissions of different origin from ZnO.Wide-gap oxide semiconductors are attractive materials as phosphors if they could exhibit visible emissions arising from defect levels created in the bandgap. However, defect-related emissions are usually sensitive to synthetic conditions and suffer from reproducibility. This inference holds true for blue band emissions possibly observed from oxide semiconductors such as ␤-Ga 2 O 3 and ZnO. ␤-Ga 2 O 3 can exhibit UV and blue emissions, which are assigned to recombination of a self-trapped exciton and a donor-acceptor pair, respectively, depending on the sample preparation conditions and the nature of defects. 1 ZnO is an n-type semiconductor having a wide bandgap of approximately 3.3 eV. Reduced ZnO, which is often termed ZnO:Zn, has been utilized as green phosphors because of its excellent luminescence properties under high-energy excitations. However, ZnO is also known to exhibit much more complicated luminescence behaviors in the visible wavelength region. Besides a UV near-band-edge emission at approximately 380 nm, visible deep-level emissions can be observed with a peak anywhere in the wide wavelength range from 450 to 730 nm. 2,3 In addition, there are some reports on the occurrence of blue band emissions centered at a shorter wavelength of 430 nm in ZnO thin films 4-7 and nanostructures. 8-11 Nonetheless, blue band emissions have been ignored so far because they have much lower intensity than the applicable green band emissions and their origin remains unclear.Recently, some important experimental results have been reported for blue emissions of ZnO. One might expect that visible luminescence of ZnO could be tailored by a bandgap broadening through quantum size effects. Actually, this kind of tuning was achieved by Xiong et al. 12 using polyether-grafted ZnO nanoparticles dispersed and stabilized in ethanol. They found that ...

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Section: J284mentioning

confidence: 99%

Blue Luminescence of MgZnO and CdZnO Films Deposited at Low Temperatures

Ogawa

Fujihara

2007

J. Electrochem. Soc.

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“…This coating/heating procedure is repeated several times to control the film thickness. Metal fluoride and oxyfluoride powders can be obtained by heating dried trifluoroacetate gels [18][19][20].…”

Section: Chemical Processing Using Tfamentioning

confidence: 99%

Chemical processing for inorganic fluoride and oxyfluoride materials having optical functions

Fujihara

Tokumo

2009

Journal of Fluorine Chemistry

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“…This PL has a large part of spectral profile overlapped with the broadband host PL, and the Eu 3+ -PL as well. However, its characteristic emission [7-9] can be recognized and identified using time-resolved technique from other PL origins. It is interesting to point out that Eu 2+ emission was not observable in the sample where no c-Si nanoparticles exist.…”

Section: Optical Sensing and Uv-induced Photoluminescencementioning

confidence: 99%

Optical and Nonlinear Optical Response of Light Sensor Thin Films

Liu

Rúa

Vasquez

et al. 2005

Sensors

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For potential ultrafast optical sensor application, both VO 2 thin films and nanocomposite crystal-Si enriched SiO 2 thin films grown on fused quartz substrates were successfully prepared using pulsed laser deposition (PLD) and RF co-sputtering techniques. In photoluminescence (PL) measurement c-Si/SiO 2 film contains nanoparticles of crystal Si exhibits strong red emission with the band maximum ranging from 580 to 750 nm. With ultrashort pulsed laser excitation all films show extremely intense and ultrafast nonlinear optical (NLO) response. The recorded holography from all these thin films in a degenerate-four-wave-mixing configuration shows extremely large third-order response. For VO 2 thin films, an optically induced semiconductor-tometal phase transition (PT) immediately occurred upon laser excitation. it accompanied. It turns out that the fast excited state dynamics was responsible to the induced PT. For cSi/SiO 2 film, its NLO response comes from the contribution of charge carriers created by laser excitation in conduction band of the c-Si nanoparticles. It was verified by introducing Eu 3+ which is often used as a probe sensing the environment variations. It turns out that the entire excited state dynamical process associated with the creation, movement and trapping of the charge carriers has a characteristic 500 ps duration.

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Synthesis Process of BaMgAl[sub 10]O[sub 17]:Eu[sup 2+] from Sol-Gel-Derived Eu[sup 2+]-Activated Fluoride Precursors without H[sub 2] Annealing Treatments

Cited by 8 publications

References 27 publications

Blue Luminescence of MgZnO and CdZnO Films Deposited at Low Temperatures

Blue Luminescence of MgZnO and CdZnO Films Deposited at Low Temperatures

Chemical processing for inorganic fluoride and oxyfluoride materials having optical functions

Optical and Nonlinear Optical Response of Light Sensor Thin Films

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