Sensitized Luminescence of Trivalent Europium by Three-Dimensionally Arranged Anatase Nanocrystals in Mesostructured Titania Thin Films

Frindell, Karen L.; Bartl, Michael H.; Popitsch, Alois; Stucky, Galen D.

doi:10.1002/1521-3773(20020315)41:6<959::aid-anie959>3.0.co;2-m

Cited by 215 publications

(166 citation statements)

References 15 publications

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“…In our previous studies, we showed that the reaction time and temperature, the size of the samples, and the concentration of the doping ions affect the UCL properties of Yb/Tm/ZnO nanoparticles [30][31][32][33][34][35][36]. In order to analyze the functional dependence of the morphology, three sets of samples were prepared with different concentrations of OH .…”

Section: Synthesismentioning

confidence: 99%

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White-light upconversion emission of lanthanide double-doped oxide nanoparticles via defect state luminescence of ZnO

Wang

et al. 2017

Sci. China Mater.

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Section: Synthesismentioning

confidence: 99%

“…In particular, ZnO nanorods have attracted great interest due to their high surface-to-volume ratio and excellent crystallite quality [30,31]. However, it is difficult to incorporate Ln 3+ ions into the ZnO lattice due to the large mismatch of ionic radii between Ln 3+ and Zn 2+ ions and the resulting imbalance in charge [32,33].…”

Section: Introductionmentioning

confidence: 99%

White-light upconversion emission of lanthanide double-doped oxide nanoparticles via defect state luminescence of ZnO

Wang

et al. 2017

Sci. China Mater.

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“…Host sensitization via the energy transfer from the excited semiconductor host to Ln 3+ is considered to be an effective way to realize highly efficient luminescence of Ln 3+ for practical applications such as optoelectronic devices and flat panel displays [51,127,187]. In general, energy transfer involves the nonradiative energy transfer from a donor (sensitizer) to an acceptor separated in a solid by distances greater than the inter-atomic separations.…”

Section: Host Sensitized Luminescencementioning

confidence: 99%

“…To this end, an effective way to assist the nonresonant energy transfer process is using defects as intermediate states. Such defect-mediated energy transfer from SNCs to Ln 3+ ions was documented in the literature [49,127]. In particular, Wang and co-workers [209] demonstrated a defect-mediated energy transfer pathway from the ZnO host to the Eu 3+ ions evidenced by temperature-dependent and time-resolved PL experiments.…”

Section: Reviewmentioning

confidence: 99%

Lanthanide-doped semiconductor nanocrystals: electronic structures and optical properties

2015

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solid state lightings [11,12]. Nevertheless, due to the parity forbidden transition nature, the absorption cross-section of f-f transition is small and usually high power light sources such as laser are needed to excite the Ln 3+ ions. The ability to excite Ln 3+ ions efficiently in a broad spectral range is strongly desired for realizing their full potentials in signaling and lighting applications. To improve the excitation efficiency of Ln 3+ , sensitization is an efficient way to avoid the direct excitation of the Ln 3+ . Charge transfer, electronics transfer from ligand ground states (e.g., O 1s) to the Ln 3+ excited states, has proved to be an efficient means to achieve intense Ln 3+ emissions, due to its large band absorption cross-section. By employing this strategy, commercial phosphor Y 2 O 3 :Eu 3+ has been demonstrated to be an excellent red phosphor, which can be effectively excited at Eu-O charge transfer band at 255 nm. Another strategy for efficient sensitization of Ln 3+ is via the energy transfer (ET) from semiconductor nanocrystals (SNCs), which generally possess large absorption cross-section for Ln 3+ excited states. Moreover, it is known that the exciton Bohr radius of semiconductors is much larger than that of insulators [13], which could result in pronounced quantum confinement effect for small nanocrystals (NCs) (e.g., 2−10 nm for In 2 O 3 , ZnO and TiO 2 ). As a result, the optical properties of Ln 3+ incorporated in SNCs could be tailored via size control or bandgap engineering, which is very attractive in fabricating a nano-device for technological applications. It is anticipated that the luminescence of Ln 3+ ions can be efficiently sensitized via the energy transfer from the excited host to Ln 3+ , which thereby overcomes the inefficient direct absorptions of the parity forbidden 4f-4f transitions of Ln 3+ ions (Fig. 1). To realize the efficient energy transfer and intense Ln 3+ PL, the successful incorporation of Ln 3+ into the lattices of SNCs is of utmost importance, which still remains a great challenge via conventional wet-chemical methods especially for some widely used wide bandgap Trivalent lanthanide (Ln 3+ ) ions doped semiconductor nanomaterials have recently attracted considerable attention owing to their distinct optical properties and their important applications in diverse fields such as optoelectronic devices, flat plane displays and luminescent biolabels. This review provides a comprehensive survey of the latest advances in the synthesis, electronic structures and optical spectra of Ln 3+ ions in wide band-gap semiconductor nanocrystals (SNCs). In particular, we highlight the general wet-chemical strategies to introduce Ln 3+ ions into host lattices, the local environments as well as the sensitization mechanism of Ln 3+ in SNCs. The energy levels and crystal-field parameters of Ln 3+ in various SNCs determined from energy-level-fitting are summarized, which is of vital importance to understanding the optical properties of Ln 3+ ions in SNCs. Finally, some future pros...

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“…[1][2][3][4][5] So far various strategies have been exerted to tailor new class of mesopore structures, to develop more convenient route to syntheses, and to understand formation mechanisms. [6][7][8][9][10][11][12] The so-called evaporation induced self-assembly (EISA) process, initiated by Brinker's group, has realized a facile fabrication of mesoporous silica thin films.…”

Section: Introductionmentioning

confidence: 99%

Derivation of Cubic and Hexagonal Mesoporous Silica Films by Spin-coating

2005

Bulletin of the Korean Chemical Society

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By introducing spin-coating method to the evaporation induced self-assembly (EISA) process, a simple and reproducible route in controlling the mesophase of silica thin films has been developed for the first time in this work. When a comparatively solvent-rich Si-sol (The atomic ratio of TEOS : F127 : HCl : H2O : EtOH = 1 : 0.006 : 0.2 : 9.2 : 30) was used as coating solution, the mesophase of resultant silica films was selectively controlled by adjusting the spin-on speed. The cubic mesophase has been obtained from the coating at a low rpm, such as 600 rpm, while the 2-D hexagonal mesophase is formed at a high rpm, such as 2,500 rpm. At a medium coating speed, a mixture of cubic and hexagonal mesophase has been found in the fabricated films. The present results confirm that the evaporation rate of volatile components at initial step is critical for the determination of mesopore structures during the EISA process.

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Sensitized Luminescence of Trivalent Europium by Three-Dimensionally Arranged Anatase Nanocrystals in Mesostructured Titania Thin Films

Cited by 215 publications

References 15 publications

White-light upconversion emission of lanthanide double-doped oxide nanoparticles via defect state luminescence of ZnO

White-light upconversion emission of lanthanide double-doped oxide nanoparticles via defect state luminescence of ZnO

Lanthanide-doped semiconductor nanocrystals: electronic structures and optical properties

Derivation of Cubic and Hexagonal Mesoporous Silica Films by Spin-coating

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