Chen Wei, Kristianpoller N, Shmilevich A, Weiss D, Chen R, Su Mianzeng
Nomadics, Inc., 1024 South Innovation Way, Stillwater, Oklahoma 74074, USA.
J Phys Chem B. 2005 Jun 16;109(23):11505-11. doi: 10.1021/jp050317r.
Temperature behaviors of X-ray luminescence (XL), photoluminescence (PL), photostimulated luminescence, and thermoluminescence (TL) were studied in BaFCl:Eu2+ single crystals from room temperature to liquid nitrogen temperature. Six emissions at 275, 315, 365, 385, 435, and 500 nm were observed in the XL spectra and are attributed to Cl excitons, V(k)(Cl2-), the 4f65d1 (2e(g)) --> 4f7 (8S(7/2)) transition of Eu2+, and oxygen vacancies, respectively. Three emission peaks at 315, 365, and 390 nm were observed in the PL and TL measurements. These three emissions are from the transitions of 4f7(6I(7/2)) --> 4f7(8S(7/2)), 4f7(6P(7/2)) --> 4f7(8S(7/2)), and 4f65d1 (2e(g)) --> 4f7(8S(7/2)) of Eu2+, respectively. In our measurements, we observed that the emission of Eu2+ increases in intensity upon beta-irradiation and did not see any signals related to Eu3+ ions, which indicates that Eu2+ ions might not be oxidized to Eu3+ upon X-ray or beta-irradiation. Instead, the color centers, Cl excitons, and oxygen defects are created and are stable at room temperature, and they might play a key role in the storage luminescence.
研究了BaFCl:Eu2+单晶在从室温到液氮温度范围内的X射线发光（XL）、光致发光（PL）、光激励发光和热释光（TL）的温度行为。在XL光谱中观察到275、315、365、385、435和500nm处的六种发射，分别归因于Cl激子、V(k)(Cl2-)、Eu2+的4f65d1(2e(g))→4f7(8S(7/2))跃迁和氧空位。在PL和TL测量中观察到315、365和390nm处的三个发射峰。这三种发射分别来自Eu2+的4f7(6I(7/2))→4f7(8S(7/2))、4f7(6P(7/2))→4f7(8S(7/2))和4f65d1(2e(g))→4f7(8S(7/2))跃迁。在我们的测量中，我们观察到Eu2+的发射在β辐照后强度增加，并且没有看到任何与Eu3+离子相关的信号，这表明Eu2+离子在X射线或β辐照下可能不会被氧化为Eu3+。相反，色心、Cl激子和氧缺陷被产生并在室温下稳定，它们可能在存储发光中起关键作用。
