Vol.:(0123456789) 1 3 Journal of Materials Science: Materials in Electronics https://doi.org/10.1007/s10854-020-03660-9 Efect of annealing on the photoluminescence and thermoluminescence properties of Eu 2+ doped BaSO 4 microgravels S. Sahaya Jude Dhas 1  · S. Suresh 2  · A. Rita 3  · S. A. Martin Britto Dhas 3  · R. Gowri Shankar Rao 4  · C. S. Biju 5 Received: 23 February 2020 / Accepted: 21 May 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract The quest for developing phosphors emitting intense ultra violet (UV) rays and thermoluminescence (TL) occurring in the temperature range between 180 and 250 °C is on the progressive surge as the phosphors are highly desirable for phototherapy lamps and X-ray dosimetry. For this work, strong UV and TL emitting Eu 2+ doped BaSO 4 gravels of sub-micro size were synthesized by acid-assisted co-precipitation method. The as-prepared phosphors were annealed at diferent temperatures (300–700 °C) for 10 h to enhance the UV and TL emissions. The infuence of annealing on the crystallite size, morphology, vibrational bands, PL and TL were studied by X-ray difraction (XRD), Field emission gun scanning electron microscopy (FEGSM), Fourier transform infrared spectroscopy (FTIR), Photoluminescence (PL) and TL spectroscopies, respectively. From XRD, it is noticed that the crystallite size and crystal quality increase when the annealing temperature is raised from 300 to 500 °C, whereas they are found to be decreasing at 600 °C and the trend continues till 700 °C. FEGSEM images show that all the phosphors have similar gravel morphology with inhomogeneous sub-micro size distribution. Formation of clusters is also noticed for phosphors while annealing in the range 300–500 °C. The vibrational bands related to the phosphor have been identifed from the FTIR spectra. From PL and TL studies, the prominent emission intensity is found to be the maximum for 500 °C annealed phosphor revealing optimization. PL spectra also exhibit a strong UV emission at ~ 374 nm. The TL glow curve of the phosphors shows the frst deconvoluted peak in the temperature range 198–210 °C and the second peak in the range 240.3–259.1 °C. The activation energy for the frst peak is in the range 1.02 to 1.30 eV, whereas the second peak is in the range 0.72 to 2.98 eV. Thus the optimized multi-utility phosphor could be benefcial for phototherapy lamps and X-ray dosimeters. 1 Introduction Over the years, there has been continuously ever increas- ing demand witnessed for rare-earth doped ultra violet (UV) emitting phosphors (Gd 3+ :ZrO 2 , Gd 3+ :BaB 8 O 13 , Gd 3+ :Y 3 Ga 5 O 12 , Eu 2+ :BaSO 4 and Eu 2+ :CaSO 4 ) [1–5] as they have consistently exhibited their strength in this proac- tive area due to large scale applications such as photother- apy lamps, production of vitamin B2 in mushrooms, liquid crystal display, radiation dosimeter, degradation of organic pollutants etc. [2, 4–10]. Among these, sulphate based compounds (CaSO 4 and BaSO 4 ) have already emerged as a prominent host for stabilizing rare-earth dopants [5, 7, 8]. In particular, Eu 2+ doped BaSO 4 with micro/nano morphology is considered as a multi-utility phosphor due to its robust nature and excellent luminescence characteristics [4]. More- over, Eu 2+ ions posses 4f–5d transitions with high absorp- tion coefcient and broad absorption range which enable the * S. Suresh sureshthanjai2003@gmail.com * C. S. Biju zlifyplanet@gmail.com 1 Department of Physics, Kings Engineering College, Sriperumbudur, Chennai, Tamil Nadu 602 117, India 2 Department of Physics, Saveetha Engineering College (Autonomous), Thandalam, Chennai, Tamil Nadu 602105, India 3 Department of Physics, Abraham Panampara Research Centre, Sacret Heart College (Autonomous), Tirupattur, Vellore, Tamil Nadu 635601, India 4 Department of Physics, Veltech Rangarajan Dr. Sagunthala R & D Institute of Science and Technology, Avadi, Chennai, Tamil Nadu 600062, India 5 Department of Physics, Malankara Catholic College, Mariagiri, Kaliakkavilai, Tamil Nadu 629153, India