Optically Functional Zeolites: Evaluation of UV and VUV Stimulated Photoluminescence Properties of Ce3+- and Tb3+-doped Zeolite X

Abstract

The optical properties of Tb 3+ /Ce 3+ doped zeolites are elucidated with emphasis on ultraviolet (UV) and vacuum ultraviolet (VUV) excitation and luminescence. Ce 3+ sensitized Tb 3+ emission with quantum yields of 85 % may be obtained at 330 nm excitation. Low absorptivity at 254 nm due to low Ce 3+ concentrations or low Ce 3+ /Tb 3+ ratios, which are required for the suppression of UV components, restricts their applicability as phosphors for Hg-based discharges, e.g., in conventional fluorescent lamps. Near band edge excitation at 172 nm revealed an immediate quantum yield of 50 % enabled by a zeolite ® Ce 3+ (5d 1 ) ® Tb 3+ (4f 7 5d 1 ) energy transfer channel, which may be exploited for the down-conversion of the Xe 2 excimer emission.

Efficient Luminescence from Rare‐Earth Fluoride Nanoparticles with Optically Functional Shells

“…The VUV system was calibrated against measurements at Philips Research Laboratories Aachen, Germany [26]. For selected Eu 3+ samples, quantum yields were estimated from reflectance and emission data obtained with an integrating sphere with a diameter of 70 mm and 10 mm port openings against commercial white and black references (Labsphere) and relative to commercial Y 2 O 3 :Eu (YOX), whose quantum yield at 272 nm was taken to be 73 % at a reflectance of 69 %.…”

Dehydration and rehydration effects on the photoluminescence properties of terbium-exchanged MFI-type materials

“…After implementing this methodology we have applied a similar uncertainly analysis. Four criteria for optimization of parameters were tested: least squares, 2 and mean value between maximum and minimum absolute deviation ((max (abs(I i (t) exp À I i (t) fit )) + min (abs(I i (t) exp À I i (t) fit )))/2). The best final criterion for the optimization of the parameters was usually the least squares.…”

“…The lanthanides-exchanged zeolites have been extensively studied in respect to their potential optical applications [1][2][3][4]. However, the quantum efficiency of luminescence (PL) of these materials is low, mainly due to the quenching effect of water molecules [5,6].…”

Synthesis and optical characterization of rare earth nanofluorides

“…The penetration or accomodation of the zeolite cages by ionic and molecular species is a well-known, phenomenon widely used for catalysis, ion exchange and molecular sieving. On the optical side, the feasibility of zeolites supported luminescence, in particular, has been demonstrated for ions, complexes and molecules [7][8][9][10]. However, most likely due to the high reactivity of the zeolite matrix towards fluorides, reports on the optical performance of encapsulated fluoride species have been presented only recently [11].…”