Multiband Orange‐Red Luminescence of Eu³⁺ Ions Based on the Pyrochlore‐Structured Host Crystal.

Abstract

Luminescence D 6540Multiband Orange-Red Luminescence of Eu 3+ Ions Based on the Pyrochlore--Structured Host Crystal. -(Y1-xEux)2Sn2O7 (x = 0.01-0.20) films are synthesized by a sol-gel method from Y(OAc)3, Eu(OAc)3, and SnCl4. Highly crystalline and phase pure samples are obtained by treating the films at 1000°C. Photoluminescence spectra indicate the simultaneous occurrence of five predominant orange-red band emissions at a single-wavelength UV excitation. The chromaticity corresponds to a region between pink and yellowish pink in the CIE diagram which could make the material useful as a new reddish component in reproducing natural light in optical devices. -(FUJIHARA*, S.; TOKUMO, K.; Chem. Mater. 17 (2005) 22, 5587-5593; Dep. Appl. Chem., Fac. Sci. Technol., Keio Univ., Kohoku, Yokohama 223, Japan; Eng.) -W. Pewestorf 03-009

Europium Complex Covalently Grafted on Si(100) Surfaces, Engineered with Covalent Polystyrene Nanostructures

“…The SA_PSS_Eu exhibits PL with a strong, sharp, and well-resolved emission at 616 nm (Figure a) that can be ascribed to the electric-dipole 5 D 0 → 7 F 2 transition of the Eu 3+ ions located at the sites without inversion symmetry. ,,,− A less intense emission peak for the 5 D 0 → 7 F 1 is also evident at 593 nm. ,,,− Other very weak PL signals are present at higher wavelength, out of the range of Figure a. ,,,− Therefore, even though they have different intensities, both electric- and magnetic-dipole transitions are evident in the present Eu(III)-monolayer . In fact, 4f levels in lanthanide compounds have been generally considered essentially atomic in nature and simple spectators with respect to the chemical bond because filled 5s 2 and 5p 6 levels shield 4f orbitals from ligand field effects.…”

“…The synthesis of hybrid organic/inorganic nanostructures on appropriate substrates represents an advanced method for the production of magnetic, electronic, and photonic devices. − Lanthanide complexes display exceptional luminescence characteristics such as high luminous intensity, long fluorescence lifetime, large Stokes shifts, and sharp emission profiles from the f–f electron transitions, which make them useful in fluorescence, DNA hybridization, cell activity, bioimaging assays, and so on. − However, pure lanthanide complexes usually have poor thermal and mechanical stabilities, which restrict their practical applications . For these reasons, lanthanide complexes have been incorporated into polymers, sol–gel precursors, and so on to obtain composite materials. − In addition, lanthanide complexes conjugated to polymers may combine their luminescence properties for improved photonic applications. − In fact, lanthanide complexes embedded in polymeric matrices have been reported to have unique luminescent properties, , and polymers are regarded as appropriate hosts for flexible, large-area displays and light-emitting diodes .…”

Structural Characterization and Luminescent Properties of a Red Phosphor Series: Y2−xEux(MoO4)3 (x=0.4–2.0)

“…Recently different authors 13,36,41 have used the ratio between integrated intensity of the transitions 5 D 0 -7 F 2 and the 5 D 0 -7 F 1 , represented as I 0À2 /I 0À1 , as a local crystal field probe to measure the nature of local cation (Eu 31 ) surroundings. We have plotted these ratios with respect to the amount of Eu 31 (x) used in the samples and is shown in Fig.…”

Preparation and Luminescence Property of Red-Emitting Hardystonite Phosphors by Near-Ultraviolet Irradiation

“…The intensity ratio of 5 D 0 -7 F 2 to 5 D 0 -7 F 1, also called the asymmetric ratio, is close to being related to the local environment of Eu 31 . 40 Generally, the larger the intensity ratio of 5 D 0 -7 F 2 to 5 D 0 -7 F 1 , the lower the local symmetry. 41 The asymmetric Table III .…”