Luminescence and decay characteristics of Tb³⁺-doped fluorophosphate glasses

Abstract

Tb 3+-doped fluorophosphate glasses with the composition of P 2 O 5-K 2 O-SrF 2-Al 2 O 3-x Tb 4 O 7 (where x = 0.1, 0.5, 1.0, 2.0 and 4.0 mol%) were prepared by a conventional high temperature melt quenching technique and characterized through absorption, emission, excitation and decay measurements. From the emission studies, a strong green emission at around 546 was observed, which corresponds to the 5 D 4 → 7 F 5 transition of Tb 3+ ion. Green/blue intensity ratios (I G /I B) were evaluated as a function of Tb 3+ concentration and vice versa. Higher I G /I B intensity ratio confirms the higher covalency between Tb-O bond and higher asymmetry around the Tb 3+ ions in the present fluorophosphate glasses. The decay curves for the 5 D 4 level of Tb 3+ ion were measured and found that they exhibited single exponential nature irrespective to the dopant concentration. The experimental lifetime was determined using single exponential fitting and found that it increased from 2.65 to 2.95 ms when Tb 3+ concentration increased from 0.1 mol% to 4.0 mol%. The derived properties were compared to the other Tb 3+-doped glasses in order to see the potentiality of the material for visible laser gain media at 546 nm.

Proton, UV, and X-ray Induced Luminescence in Tb3+ Doped LuGd2Ga2Al3O12 Phosphors

“…The decay time analysis is very handy in order to understand the energy transfer mechanism and luminescence quenching of Tb 3+ ions. The investigation of these decay curves clarify that decay time gets shorter if Tb 3+ concentration is decreased from 3 mol% to 1 mol% as mentioned in other articles [23,28]. In other words, we can say that beyond 3 mol% the concentration quenching starts, which in turn delays the emission process.…”

“…It also describe the symmetry of the local environment around the optically active dopant and covalent/ ionic bonding between Tb 3+ and O 2− . Similar to Eu 3+ or Dy 3+ , the Tb 3+ ions may be used as a spectroscopic probe as well [23,24].…”

Scintillating glass‐ceramic substrates for indirect flat panel detectors in digital radiography

“…The authors surmise that the difference is largely due to the different mean lifetimes of the two luminescent centers and the integration times of the two instruments used to measure the spectra. Barium chloride is a very fast scintillator with a mean lifetime on the order of nanoseconds, while Tb 3+ is much slower with a lifetime on the order of milliseconds 23,27 . The phosphorimeter used to measure the UV‐excited spectrum employed a 50 µs integration time, which is sufficient to capture the entirety of the BaCl 2 emission, but only a fraction of the Tb 3+ emission.…”

“…22 Interestingly, the shape of the peak attributed to BaCl 2 changes with increased Tb 2 O 3 content in the sample; these changes are attributed to absorption of the BaCl 2 emission by Tb 3+ at 417 ( 7 F 5 → 5 D 3 ) and 439 nm ( 7 F 4 → 5 D 3 ). 23 The violet and UV emission of BaCl 2 is not optimal for amorphous silicon photodiode detectors, commonly used in flat panel detectors, but is useable. 24 The green emission of Tb 3+ better matches the quantum efficiency curve of the amorphous silicon detector, but its presence diminishes the detectable emission from BaCl 2 ; to be beneficial in the proposed application, the total number of photons from Tb 3+ , either X-ray or photoexcited, perceived by the detector must be greater than the number of absorbed photons from the BaCl 2 that would be otherwise detected.…”

“…Barium chloride is a very fast scintillator with a mean lifetime on the order of nanoseconds, while Tb 3+ is much slower with a lifetime on the order of milliseconds. 23,27 The phosphorimeter used to measure the UV-excited spectrum employed a 50 µs integration time, which is sufficient to capture the entirety of the BaCl 2 emission, but only a fraction of the Tb 3+ emission. The CCD spectrometer used for the X-ray-excited emission spectrum employed a much longer integration time, 35 ms, and therefore detected a greater amount of Tb 3+ emission; this longer integration time is similar to that of flat panel detectors used in digital radiography, which can have frame rates of 30 fps (33 ms per frame).…”