Multilevel based analysis of the thermoluminescence of CaSO4:RE (RE=Tm, Dy, Tb, and Sm)

Abstract

Vacuum ultraviolet spectroscopic properties of rare earth ( RE = Ce , Tb , Eu , Tm , Sm ) -doped hexagonal K Ca Gd ( P O 4 ) 2 phosphateThe thermoluminescence activation energy and frequency factor of the main glow of Ca S O 4 : Tm phosphor determined by heating rate method including very slow rates of heating Multitrapping levels feature of thermoluminescent ͑TL͒ phosphors of CaSO 4 :RE ͑RE= Dy, Tb, and Sm͒ were analyzed using a variable heating rate method ͑including extremely slow heating rates of 0.001°C s −1 ͒, the postannealing method, and the analysis of TL decay curves using x-ray induced luminescence ͑XIL͒ spectroscopy after x-ray excitation was cut off at temperatures between 100 and 240°C. All the data confirmed the multilevel feature of the TL levels. The ranges of activation energies E of these components in the main glow were determined to be ͑a͒ 1.64-2.03 eV for CaSO 4 : Dy, ͑b͒ 1.66-2.01 eV for CaSO 4 : Tb, and ͑c͒ 1.66-2.00 eV for CaSO 4 : Sm. The frequency factor s was determined to be 10 19 s −1 for all components of the phosphors. The previously reported TL properties of the CaSO 4 : Tm phosphor were reinvestigated using the XIL decay analysis. Assuming that the most populated level is located at the center of the main glow, the four phosphors have similar E values of ϳ1.8 eV. The present results imply that the multicomponent TL properties of rare-earth-doped CaSO 4 phosphors are characterized by a lattice of CaSO 4 involving defects introduced around RE 3+ ions, and the glow curve properties are essentially not dependent on the rare-earth species introduced.

Synthesis and luminescent properties of CaMoO4:Tb3+, R+ (Li+, Na+, K+)

“…Thus, the introduction of trivalent rare earth ions as luminescent center to matrices is considered as an excellent method for preparing superior luminescent material [1][2][3][4].…”

Influence of Li dopants on thermoluminescence spectra of CaSO4 doped with Dy or Tm

“…These sulphates are widely used for both individual and environmental radiation monitoring [1][2][3]. Their popularity has led to an extensive series of studies aimed at elucidating their behavior, attempting to assess the underlying mechanisms, and efforts to predict, or empirically develop new variants of these phosphors [4][5][6][7][8][9][10]. One particularly interesting result was reported by Dr Prokic who found that the addition of a lithium co-dopant during preparation of the CaSO 4 :Dy (or Tm) results in a major increase of luminescence efficiency.…”

Surfactant-Free Synthesis of CaSO[sub 4] Nanorod/Nanowire by Electrochemical Deposition

“…17 In addition, rare-earth-doped CaSO 4 shows useful thermoluminescence for the potential application in photoluminescence crystal liquid displays, optical storage materials, and cathodoluminescent materials. 18,19 Various methods have been used for the synthesis of CaSO 4 nanoparticles, [20][21][22][23] nanorods, 23 nanowires, 20,21,[23][24][25] and nanosheets, 21 such as water-in-oil microemulsion and reverse micelles, 20,23,26 a microwave-assisted method, 25 and a liquid-liquid separation method. 22 However, these methods have limitations in growth time, large quantity synthesis, and substrate synthesis.…”