Synthesis, structural and spectroscopic investigations of nanostructured samarium oxalate crystals G. Vimal, Kamal P. Mani, P.R. Biju, Cyriac Joseph ⇑ , N.V. Unnikrishnan, M.A. Ittyachen School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560, India highlights  First time report on nanostructured Samarium oxalate crystals.  The mechanism of aggregation of nanocrystals as nanoplates is explained.  Spectroscopic parameters are evaluated using Judd–Ofelt theory.  Suitability of the materials as a phosphor was confirmed by fluorescence study. graphical abstract article info Article history: Received 7 August 2013 Received in revised form 7 November 2013 Accepted 13 November 2013 Available online 20 November 2013 Keywords: Nanocrystal Photoluminescence Judd–Ofelt analysis Branching ratio Phosphor material abstract Nanostructured samarium oxalate crystals were prepared via microwave assisted co-precipitation method. The crystal structure and morphology of the sample were analyzed using X-ray powder diffrac- tion, Scanning electron microscopy and Transmission electron microscopy. The presence of functional groups is ascertained by Fourier transform infrared spectroscopy. Samarium oxalate nanocrystals of aver- age size 20 nm were aggregated together to form nano-plate structure in sub-microrange. Detailed spec- troscopic investigation of the prepared phosphor material was carried out by Judd–Ofelt analysis based on the UV–Visible–NIR absorption spectra and photoluminescence emission spectra. The analysis reveals that the transition from energy level 4 G 5/2 to 6 H 7/2 of Sm 3+ ion has maximum branching ratio and the cor- responding orange emission can be used for display applications. Ó 2013 Elsevier B.V. All rights reserved. Introduction Nanostructured materials are the subject of extensive research in recent years due to their versatile applications in most of the fields of modern technology owing to their interesting physical properties which can be governed by optimizing the size, morphol- ogy and structure. Various synthesis methods are developed to prepare nanostructured materials with different pre-assigned morphologies such as nanowires, nanorods, and nanoplates with tunable size [1,2]. In the nanometer regime the physical properties are highly altered by the presence of significant number of surface atoms, quantum confinement electronic states etc. which leads to the novel properties compared with their corresponding bulk phases. Rare earth based nanosystems gained considerable atten- tion due to their potential applications in the fields of optical de- vices, solid oxide fuel cells, and high strength permanent magnets due to their unique optical, electric and magnetic proper- ties respectively [3–5]. The distinctive properties of the rare earth compounds originate from the electronic transitions within the 4f shell of the rare earth ion which are shielded by 5s and 5p elec- trons but highly sensitive to the characteristics of the host lattice 1386-1425/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.saa.2013.11.080 ⇑ Corresponding author. Tel.: +91 04812731043. E-mail address: cyriacmgu@gmail.com (C. Joseph). Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 122 (2014) 624–630 Contents lists available at ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa