A study of the luminescence in near UV-pumped red-emitting novel Eu 3+ -doped Ba 3 Ca 3 (PO 4 ) 4 phosphors for white light emitting diodes G.R. Dillip a , B. Deva Prasad Raju a,b,⇑ a Department of Physics, Sri Venkateswara University, Tirupati 517 502, India b Department of Future Studies, Sri Venkateswara University, Tirupati 517 502, India article info Article history: Received 8 May 2012 Accepted 2 June 2012 Available online 22 June 2012 Keywords: Inorganic phosphors Diffuse reflectance spectroscopy FE-SEM White LEDs abstract Rare-earth ions doped inorganic luminescent materials (phosphors) in nanodimensions find widespread scientific and industrial applications. This paper report a novel red-emitting Eu 3+ doped Ba 3 Ca 3 (PO 4 ) 4 phosphors in nanodimensions were synthesized via one-step conventional solid state reaction method for first time at high temperature in air atmosphere. The morphology and nanostructures of synthesized phosphors were determined by powder X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM) and Energy-dispersive X-ray spectroscopy (EDS). The XRD observation reveals that the undoped and Eu 3+ doped Ba 3 Ca 3 (PO 4 ) 4 phosphors are in single crystalline phase with the sizes of 40–65 nm. FE-SEM image indicated the phosphor is composed of nearly spherical particles and rod like structures with several nanometer sizes. The presence of orthophosphates in Ba 3 Ca 3 (PO 4 ) 4 phosphor was identified by Fourier transform infrared (FT-IR) analysis and the thermal stability was studied by Differ- ential scanning calorimetry (DSC). Diffuse reflectance spectra (DRS) evidenced the incorporated Eu 3+ ions in host material. In addition, the bandgap of these samples were estimated from the Mubelka–Munk function. The room-temperature photoluminescence spectra show the characteristic red fluorescence originating from intra 4f 5 D 0 ? 7 F 2 (616 nm) transition of Eu 3+ is observed by introducing Eu 3+ ions in Ba 3 Ca 3 (PO 4 ) 4 phosphors. The calculated color coordinates are lies in the orange–red region. Therefore, these obtained results suggest that the prepared phosphors exhibit great potential for use as red-compo- nent for near ultraviolet white light emitting diodes (NUV WLEDs). Ó 2012 Elsevier B.V. All rights reserved. 1. Introduction Now-a-days, the synthesized particles in nanoscale are essential for ongoing device improvements and miniaturization. The nano- particles are needed for a better display resolution, smaller pixel sizes and so on. The phosphate-based luminescent materials in nanodimensions have received considerable attention owing to their potential application in solid-state lighting, which could be supplanting the conventional incandescent and fluorescent lamps in the coming future. Rare-earth ions doped nanometer sized pow- der phosphors have emerged as a new class of luminescence mate- rials with superior performance characteristics such as high stability, brightness and flexible over their micrometer counter- parts [1–3]. The technological applications of lanthanide inorganic luminescent materials embraces not only display devices, such as plasma display panel (PDP) and field emission display (FED), but also lasers, optoelectronics and also as fluorescent markers in bio- medicine [4–6]. Rare earth ions have been playing an important role in modern lighting and display field due to the abundant emis- sion colors based on their 4f–4f or 5d–4f transitions. Currently, much effort have been directed towards white light emitting diodes (WLEDs) owing to their excellent properties such as long lifetime, high durability, low power consumption, high lumines- cence efficiency and environmental friendliness [7–10]. Owing to their strong red emission, mainly research is focused on novel Eu 3+ doped nanocrystalline materials. For instance, many efforts have been paid to investigate the properties of nanodimension Y 2 O 2 S:Eu 3+ and Y 2 O 3 :Eu 3+ due to its the unprecedented red emit- ting phosphor with chemical stability under UV or VUV excitation. Unfortunately, the Y 2 O 2 S:Eu 3+ and Y 2 O 3 :Eu 3+ based phosphors has low emission efficiency and are relatively expensive. From the view point of WLEDs applications, in order to supplant these de- vices, it is necessary to explore the non-rare-earth hosts with low costs and high quantum efficiency, because in many cases, the quantum efficiency for red emission is still limited [11–14]. To obtain red luminescent materials with high quantum efficien- cies, several factors, including the nature of host matrix, energy transfer, and lattice modifications, should be taken into account. A series of rare-earth ions doped phosphate host phosphors such as KCaPO 4 [15], NaCaPO 4 [16], NaBaPO 4 [17], SrMg 2 (PO 4 ) 2 0925-8388/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jallcom.2012.06.009 ⇑ Corresponding author at: Department of Future Studies, Sri Venkateswara University, Tirupati 517 502, India. E-mail address: drdevaprasadraju@gmail.com (B. Deva Prasad Raju). Journal of Alloys and Compounds 540 (2012) 67–74 Contents lists available at SciVerse ScienceDirect Journal of Alloys and Compounds journal homepage: www.elsevier.com/locate/jalcom