Luminescence Studies of Eu3+ Doped Calcium Bromofluoride Phosphor

The present paper reports photoluminescence (PL) and thermoluminescence (TL) properties of rare earth-doped calcium bromo-fluoride phosphor. The europium (Eu3+) was used as rare earth dopant. The phosphor was prepared by Solid state reaction method (conventional method). The PL emission spectrum of the prepared phosphor shows intense peaks in the red region at 611？nm for 5D0→7F2 transitions, and the PL excitation spectra show a broad band located around 220–400？nm for the emission wavelength fixed at 470？nm. The TL studies were carried out after irradiating the phosphor by UV rays with different exposure time. The glow peak shows second-order kinetics. The present phosphor can act as host for red light emission in display devices. 1. Introduction Rare earth-doped phosphors have been the center of attraction as luminescent materials from the last many decades. These phosphors have caused great attention to use as the host materials for X-ray screens, neutron detectors, alpha-particle scintillators, and so forth, due to their high luminescence efficiency and are also used as emissive materials in various display devices like LCD, FET, and CRT or as illumination sources [1–3]. Spectroscopic studies of these phosphors play a vital role in characterizing the specific luminescence properties such as photoluminescence and thermoluminescence. The rare earths are usually incorporated in these materials as divalent or trivalent cation for the realization of optically active materials in photonics and optoelectronic applications. The europium is efficiently used as luminescent center in phosphors for various purposes. Phosphors doped with europium ions are of greater importance for observing red colors on the monitors of various display devices [4]. 2. Experimental Method By solid state reaction process, CaF2, KBr, and Eu2O3 were mixed in stoichiometric ratio by dry grinding in mortar and pestle for nearly 45 minutes. The mixture is taken in quartz boat and is fired in air at 730°C for 3 hours in presence of urea. The photoluminescence studies were carried out using RF5301 spectrophotofluorometer in the wavelength range 400–650？nm at room temperature. The thermoluminescence studies were carried out using TLD reader I1009 supplied by Nucleonix System Pvt. Ltd., Hyderabad [5]. The sample was irradiated by UV radiation 365？nm. The heating rate used for TL measurement is 3°C/s. Curves were analyzed by using computer glow curve deconvolution program. 3. Result and Discussion 3.1. Photoluminescence Studies 3.1.1. PL Excitation Spectra Figure 1 shows the PL excitation