TY - JOUR
T1 - Gamma radiation-induced photoluminescence in calcium phosphate glass and inhibiting effect from copper
AU - Jiménez, José A.
AU - Crawford, Charles L.
N1 - Funding Information:
Continuing with the comparative assessment, the optical transmission of the glasses heat-treated after the gamma ray irradiation were subjected to the evaluation of the optical band gap and Urbach tails. The corresponding Tauc and Urbach plots are shown in Fig. 7 (a) and (b), respectively. Following the procedure described above for the gamma-irradiated glasses, the linear portions of the plots were analyzed to extract the different values for the band gap (Eopt) and Urbach energy (EU). The results obtained are summarized in Table 2. The band gap energy estimated for the CNP-Rad-HT glass at 3.48 (±0.05) eV appeared larger than the CNP-Rad one of 3.38 (±0.06) eV (Table 1), and approached the reported for the pristine 3.59 (±0.05) eV [25]. Thus, the recovery effect of the EC defects accompanying the thermal bleaching of the color centers is supported [9]. The Eopt value for the CuCNP1-Rad-HT was estimated at 3.53 (±0.09) eV, again higher than the CuCNP1-Rad of 3.46 (±0.09) eV (Table 1), and in good agreement with the pristine CuCNP1 reported at 3.56 (±0.09) eV [25]. The CuCNP2-Rad-HT glass however yielded a value of 2.90 (±0.07) eV. Although it somewhat lower than the irradiated (Table 1) and pristine [25] counterparts at 3.12 (±0.11) and 3.10 (±0.11) eV, respectively, it is in close proximity considering the estimated errors. Lastly, for the CuCNP3-Rad-HT glass the Eopt was estimated at 1.84 (±0.02) eV in good agreement with the values of the irradiated (Table 1) and pristine [25] counterparts at 1.82 (±0.02) and 1.83 (±0.02) eV, respectively.This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Visiting Faculty Program (VFP). Additional funding was obtained through the Laboratory Directed Research and Development (LDRD) program within the Savannah River National Laboratory (SRNL), currently operated by Battelle Savannah River Alliance (BSRA) for the U. S. Department of Energy under Contract No. 89303321CEM000080. The authors are grateful to Christopher Verst from SRNL for the gamma radiation processing. J.A. Jiménez thanks undergraduate student Victoria Ibarra from the Department of Chemistry and Physics at Augusta University for the support with the research activities.
Funding Information:
This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Visiting Faculty Program (VFP) . Additional funding was obtained through the Laboratory Directed Research and Development (LDRD) program within the Savannah River National Laboratory (SRNL) , currently operated by Battelle Savannah River Alliance (BSRA) for the U. S. Department of Energy under Contract No. 89303321CEM000080. The authors are grateful to Christopher Verst from SRNL for the gamma radiation processing. J.A. Jiménez thanks undergraduate student Victoria Ibarra from the Department of Chemistry and Physics at Augusta University for the support with the research activities.
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/5
Y1 - 2022/5
N2 - The influence of gamma-ray irradiation on the optical properties of 50P2O5–30CaO–20Na2O glass and quaternary ones prepared with [CuO]/[Na2O] molar ratios of 0.1, 0.7 and 1.5 at fixed [P2O5]/[CaO] is reported. The glasses prepared by melting were subjected to 100 kGy Co-60 gamma ray irradiation and studied by optical transmission and photoluminescence (PL) spectroscopy. The gamma-irradiated 50P2O5–30CaO–20Na2O ternary developed a ruby-red color and showed absorption features around 425 and 500 nm attributed to oxygen hole centers. The quaternary with [CuO]/[Na2O] molar ratio of 0.1 merely showed a weak absorption feature around 425 nm, whereas the highest molar ratios did not show significant differences relative to the pristine. Analyses of band gap and Urbach energies were made to aid in evaluating radiation-induced changes. Further, the irradiated copper-free glass exhibited a distinct blue luminescence band around 415 nm (not observed prior). It was most favorably excited in the UV at 265 nm, suggesting a phosphorus electron center at its origin. Its decay kinetics appeared relatively slow with a first-order exponential decay with lifetime of 4412 (±4) μs. Conversely, such emission was not detected for the copper-containing glasses, which instead exhibited PL properties comparable to the unirradiated counterparts. Finally, the effect of heat treatment after the gamma ray exposure was evaluated. The radiation-induced color centers showed a bleaching effect whereas the new PL vanished thus supporting the defects-related origin.
AB - The influence of gamma-ray irradiation on the optical properties of 50P2O5–30CaO–20Na2O glass and quaternary ones prepared with [CuO]/[Na2O] molar ratios of 0.1, 0.7 and 1.5 at fixed [P2O5]/[CaO] is reported. The glasses prepared by melting were subjected to 100 kGy Co-60 gamma ray irradiation and studied by optical transmission and photoluminescence (PL) spectroscopy. The gamma-irradiated 50P2O5–30CaO–20Na2O ternary developed a ruby-red color and showed absorption features around 425 and 500 nm attributed to oxygen hole centers. The quaternary with [CuO]/[Na2O] molar ratio of 0.1 merely showed a weak absorption feature around 425 nm, whereas the highest molar ratios did not show significant differences relative to the pristine. Analyses of band gap and Urbach energies were made to aid in evaluating radiation-induced changes. Further, the irradiated copper-free glass exhibited a distinct blue luminescence band around 415 nm (not observed prior). It was most favorably excited in the UV at 265 nm, suggesting a phosphorus electron center at its origin. Its decay kinetics appeared relatively slow with a first-order exponential decay with lifetime of 4412 (±4) μs. Conversely, such emission was not detected for the copper-containing glasses, which instead exhibited PL properties comparable to the unirradiated counterparts. Finally, the effect of heat treatment after the gamma ray exposure was evaluated. The radiation-induced color centers showed a bleaching effect whereas the new PL vanished thus supporting the defects-related origin.
KW - Gamma rays
KW - Optical transmission
KW - Phosphate glasses
KW - Photoluminescence spectroscopy
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U2 - 10.1016/j.optmat.2022.112262
DO - 10.1016/j.optmat.2022.112262
M3 - Article
AN - SCOPUS:85127111015
SN - 0925-3467
VL - 127
JO - Optical Materials
JF - Optical Materials
M1 - 112262
ER -