1 Effect of Calcination Temperature on Structural, Photoluminescence, 2 and Thermoluminescence Properties of Y 2 O 3 :Eu 3+ Nanophosphor 3 R. Hari Krishna, †,‡ B. M. Nagabhushana,* ,‡ H. Nagabhushana, § N. Suriya Murthy, ∥ S. C. Sharma, § 4 C. Shivakumara, ⊥ and R. P. S. Chakradhar* ,○ 5 † Visvesvaraya Technological University, Belgaum 590 018, India 6 ‡ Department of Chemistry, M. S. Ramaiah Institute of Technology, Bangalore 560 054, India 7 § Centre for Nanoscience Research (CNR), Tumkur University, Tumkur 572 103, India 8 ∥ Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India 9 ⊥ Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, India 10 ○ CSIR-National Aerospace Laboratories, Bangalore 560017, India 11 ABSTRACT: Red light emitting cubic Y 1.95 Eu 0.05 O 3 nano- 12 phosphors have been synthesized by a low temperature 13 solution combustion method using ethylene diamine tetra 14 acetic acid (EDTA) as fuel. The systematic studies on the 15 effect of calcination temperature on its structural, photo- 16 luminescence (PL), and thermoluminescence (TL) properties 17 were reported. The crystallinity of the samples increases, and 18 the strain is reduced with increasing calcination temperature. 19 SEM micrographs reveal that samples lose their porous nature 20 with an increase in calcination temperature. Photolumines- 21 cence (PL) spectra show that the intensity of the red emission (612 nm) is highly dependent on the calcination temperature and 22 is found to be 10 times higher when compared to as-formed samples. The optical band gap (E g ) was found to reduce with an 23 increase of calcination temperature due to reduction of surface defects. The thermoluminescence (TL) intensity was found to be 24 much enhanced in the 1000 °C calcined sample. The increase of PL and TL intensity with calcination temperature is attributed 25 to the decrease of the nonradiative recombination probability, which occurs through the elimination of quenching defects. The 26 trap parameters (E, b, s) were estimated from Chen’s glow peak shape method and are discussed in detail for their possible usage 27 in dosimetry. 1. INTRODUCTION 28 There has been a great demand for the development of new 29 types of thermoluminescence dosimeter (TLD) phosphors for 30 measuring high doses of ionizing radiation levels in personal 31 and environmental fields. In this connection, significant 32 advancements have been made in thermoluminescene (TL) 33 experiments during the last couple of decades. However, the 34 most important application of TL lies in radiation dosimetry 1,2 35 which spans areas of health physics and other biological 36 sciences, radiation protection, and personnel monitoring. TL 37 experiments are equally helpful in defects and impurities related 38 studies in solids. There are a number of commercially available 39 thermoluminescent dosimeters (TLD), the most popular being 40 LiF:Mg,Ti (TLD-100); CaSO 4 :Dy (TLD-900); LiF:Mg,Cu,P 41 (TLD-00H); CaF 2 :Dy (TLD-200); and Al 2 O 3 (TLD-500). 3 42 However, efforts are still being made to improve the TL 43 characteristics of these materials by preparing them using 44 different techniques or by developing some new ones. 45 Rare earth oxides are more stable than sulfur-containing 46 phosphors, which undergo changes in surface chemistry when 47 interacting with the electron beam, seriously degrading their 48 PL, CL brightness, and releasing gases that can poison the field 49 emitting tips. 4,5 Y 2 O 3 :RE 3+ nanoparticles are widely used as red 50 phosphor in display materials. In addition, they have been used 51 in fluorescent lamps, projection televisions, and FEDs 5−9 due to 52 their high chemical stability and good corrosion resistivity. 10 53 The luminescence of Eu 3+ is particularly interesting because 54 its major emission is centered at 612 nm (red). Red emission is 55 interesting, since it is one of the three primary colors (namely, 56 red, blue, and green) from which a wide spectrum of colors can 57 be generated by appropriate mixing. This strategy is in fact used 58 for white light generation as well. For this reason, Eu 3+ has been 59 thoroughly investigated as a luminescent activator in many host 60 lattices. 11,12 Various chemical methods have been employed for 61 preparing high-quality Y 2 O 3 :Eu 3+ materials such as gas-phase 62 condensation, 13 coprecipitation method, 14 electrochemical 63 synthesis, 15 sol−gel, 16 pyrolysis, 17 solid- to liquid-phase 64 chemical route, 18 combustion method, 19 and hydrothermal/ 65 solvothermal method. 20,21 A considerable amount of work has 66 been reported on PL and other physical properties of Received: September 29, 2012 Revised: November 30, 2012 Article pubs.acs.org/JPCC © XXXX American Chemical Society A dx.doi.org/10.1021/jp309684b | J. Phys. Chem. C XXXX, XXX, XXX−XXX jem00 | ACSJCA | JCA10.0.1465/W Unicode | research.3f (R3.4.i1:3887 | 2.0 alpha 39) 2012/09/13 09:54:00 | PROD-JCAVA | rq_2057917 | 12/26/2012 16:23:36 | 10