Photoluminescence and thermoluminescence study of KCaSO 4 Cl doped with Dy and Ce synthesized by acid distillation method Bhushan P. Kore a , N.S. Dhoble b , S.P. Lochab c , S.J. Dhoble a,n a Department of Physics, RTM Nagpur University, Nagpur 440033, India b Department of Chemistry, Sevadal Mahila Mahavidyalaya, Nagpur 440009, India c Inter-University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110067, India article info Article history: Received 19 April 2013 Received in revised form 21 June 2013 Accepted 10 July 2013 Available online 29 July 2013 Keywords: Acid distillation Luminescence Glow curve Deconvolution Dosimetry abstract Photoluminescence and thermoluminescence properties of KCaSO 4 Cl doped with dysprosium and cerium have been studied. Dy/Ce doped KCaSO 4 Cl phosphors were synthesized by the acid distillation method. The samples were characterized by XRD, SEM, PL and TL for structural, morphological and luminescence studies. The SEM image analysis of KCaSO 4 Cl phosphor shows nearly spherical particles with diameter varying between 3–10 μm. In the present host Dy 3+ emission at 482 and 573 nm is observed due to 4 F 9/2 - 6 H 15/2 and 4 F 9/2 - 6 H 13/2 transition, respectively, whereas the PL emission spectra of KCaSO 4 Cl:Ce phosphor shows two luminescence bands at 307 nm and 326 nm and are attributed to the allowed inter configurational transitions from the 5d-level to the 2 F 5/2 and 2 F 7/2 levels of Ce 3+ ion. Effect of annealing on the structure of the glow curve is investigated for KCaSO 4 Cl:Dy phosphors. Thermoluminescence linearity has been studied for 0.1–9000 Gy dose of gamma rays. Linear behavior over a large dose range between 0.1 Gy and 170 Gy was found. In addition to this trap parameters of KCaSO 4 Cl:Dy were studied using computerized glow curve deconvolution. & 2013 Elsevier B.V. All rights reserved. 1. Introduction Luminescent materials have sparked significant attention for their practical and promising applications in display devices and medical applications [1–4]. In particular, trivalent dysprosium doped phosphors have been investigated extensively because of the intense visible and wide range emission from 400 nm to 700 nm applicable for various lighting devices [5–8]. The rare earth Dy 3+ ions have two dominant emission bands in the blue and yellow region. The blue emission (470–500 nm) is due to 4 F 9/2 - 6 H 15/2 transition and the yellow emission (560–600 nm) is due to 4 F 9/2 - 6 H 13/2 transition [6,9]. The yellow emission of Dy 3+ is especially hypersensitive to the local environment. By modifying the crystal structure, the intensity ratio I Yellow /I Blue can be con- trolled and resultant color of the phosphors can be tuned. By adjusting the yellow to blue intensity ratio it is possible to achieve proximate white light emission [8]. The position of the excited 5d levels of the trivalent lanthanides in inorganic host matrix relative to the 4f n ground state config- uration is essential for many luminescence properties of phos- phors. Position of these 5d bands relative to 4f levels is also crucial for many applications of luminescent inorganic materials [10]. The positions of these 5d levels depend strongly on the crystalline environment and may change from few to tens of thousands cm À1 , from compound to compound [11–13]. In scintillation crystals, Ce 3+ is of interest as activator ion. Ce 3+ usually shows a fast dipole allowed luminescence with typically 10 750 ns decay time [14]. Since the 4f–5d transitions of Ce 3+ are parity allowed and its luminescence decay constant is usually several tens of nanoseconds. Because of this fast decay characteristic, Ce 3+ acti- vated luminescent materials are important scintillators to detect X/γ rays or thermal neutrons [15–17]. Thermoluminescence (TL) is a very common method used for estimations of doses of ionizing radiations. It has been found that the intensity and area of TL glow peaks are proportional to the received dose and this is the basis for using TL phosphors in dosimetry of ionizing radiations [18]. Various TL investigations have shown that defect centers play a crucial role in TL since, the release of holes/electrons from defect centers at characteristic traps initiate the luminescence process in the material. The demand for dosimetry of ionizing radiations is growing day by day because of its utility in all branches of science where ionizing radiation is used and variety of medical applications including radiation therapy, diagnostic radiology, and radiotherapy mailed dosimetry [19–21]. Thermoluminescence properties of sulfate based phosphors activated by different rare earths have been the subject of intense research for many years. These studies have resulted in a variety of applications [22,23]. Those TL materials Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jlumin Journal of Luminescence 0022-2313/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jlumin.2013.07.030 n Corresponding author. Tel.: +91 9822710204. E-mail address: sjdhoble@rediffmail.com (S.J. Dhoble). Journal of Luminescence 145 (2014) 299–306