Structural studies and physical properties of novel Sm 3 þ -doped Sb 2 Se 3 nanorods Abdolali Alemi a,1 , Younes Hanifehpour a,b , Sang Woo Joo b,n , Bong-Ki Min c a Department of Inorganic Chemistry, Faculty of Chemistry, University of Tabriz, Iran b School of Mechanical Engineering, WCU Nano Research Center, Yeungnam University, Gyeongsan 712-749, South Korea c Center for Research Facilities, Yeungnam University, Gyeongsan 712-749, South Korea article info Article history: Received 27 June 2011 Received in revised form 4 July 2011 Accepted 5 July 2011 Available online 13 July 2011 Keywords: Nanorods Luminescence Semiconductors Co-reduction Samarium abstract Sm 3þ doped Sb 2 Se 3 nanorods were synthesized by the co-reduction method at 180 1C and pH¼12 for 48 h. Powder XRD patterns indicate that the Sm x Sb 2x Se 3 crystals (x ¼0.00–0.05) are isostructural with Sb 2 Se 3 . The cell parameters increase for Sm 3þ upon increasing the dopant content (x). SEM images show that doping of Sm 3 þ ions in the lattice of Sb 2 Se 3 results in nanorods. High-resolution transmission electron microscopic (HRTEM) studies reveal that the Sm 0.05 Sb 1.95 Se 3 is oriented in the [1 0 1] growth direction. UV–vis absorption reveals mainly electronic transitions of the Sm 3þ ions in doped nanomaterials. Emission spectra of doped materials, in addition to the characteristic red emission peaks of Sb 2 Se 3 , show other emission bands originating from f–f transitions of the Sm 3þ ions. The electrical conductance of Sm-doped Sb 2 Se 3 is higher than undoped Sb 2 Se 3 and increase with temperature. & 2011 Elsevier B.V. All rights reserved. 1. Introduction Rare earth ions doped inorganic nanomaterials with various compositions have become an increasingly important research topic, and opened up the opportunity for creating new applica- tions in diverse areas, such as light emitting displays, biological labeling and imaging [1–3]. Antimony selenide, an important member of these V 2 VI 3 compounds, is a layer-structured semi- conductor of orthorhombic crystal structure, and exhibits good photovoltaic properties and high thermoelectric power (TEP), which allows possible applications for optical and thermoelec- tronic cooling devices [4–8]. Studies of impurity effects or doping agents on the physical properties of Sb 2 Se 3 are interesting both for basic and applied research. Doping of trivalent cations such as Sb 3 þ [9], In 3 þ [10], Fe 3 þ [11], Mn 3 þ [12] and a number of further trivalent 3d elements [13] to the lattice of Bi 2 Se 3 have been investigated, and also EPR spectra of Gd-doped bulk Bi 2 Se 3 [14]. New Ln x Bi 2 x Se 3 (Ln: Sm 3 þ , Eu 3 þ , Gd 3 þ , Tb 3 þ , Nd 3 þ ) based nanomaterials were synthesized by Alemi et al. [15,16]. Recently, we have reported novel luminescent nanomaterials based on doping of Lanthanide (Ln: Ho 3 þ , Nd 3 þ , Lu 3 þ ) into the lattice of Sb 2 S 3 [17]. However, there is no report about doping of lanthanide cations into the lattice of Sb 2 Se 3 . The incorporation of large electropositive ions such as lanthanides into antimony chalco- genide frameworks is expected to lead to materials with various properties. The incorporation of lanthanide ions into a Sb–Se framework could dramatically affect the electronic properties of that framework. In this research, nanorods of Sm x Sb 2x Se 3 crystals (x ¼ 0.00–0.05) were synthesized by introducing small amounts of Sm 3 þ to the Sb 2 Se 3 lattice. Structural, spectroscopic properties and electrical conductivity of the synthesized materials are reported. 2. Experimental section All chemicals were of analytical grade, and were used without further purification. Gray selenium (1 mmol) and NaOH (5 mmol) were added to distilled water (60 mL), and stirred well for 10 min at room temperature. Afterwards, hydrazinium hydroxide (2 mL, 40 mmol), SbCl 3 (2, 1.98, 1.96, 1.95 mmol) and Sm 2 O 3 (0.00, 0.02, 0.04, 0.05 mmol) were added, and the mixture was transferred to a 100 mL Teflonlined autoclave. The autoclave was sealed, maintained at 180 1C for 48 h, and then cooled to room temperature. The optimum conditions for this reaction are pH¼ 12, temperature 180 1C and reaction time 48 h. The black precipitate obtained was filtered and washed with ethanol and water. It was dried at room temperature. Yields for the products were 90–95%. Phase identifica- tion was performed with an Xray powder diffractometer (XRD D5000 Siemens) with CuK a radiation. The morphology of materials was examined by a scanning electron microscope SEM (Hitachi S-4200).The HRTEM image and SAED pattern were recorded by a Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/physb Physica B 0921-4526/$ - see front matter & 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.physb.2011.07.005 n Corresponding author. Tel.: þ82 538101456. E-mail addresses: Alemi.aa@gmail.com (A. Alemi), swjoo@yu.ac.kr (S.W. Joo). 1 Tel.: þ98 4113393130. Physica B 406 (2011) 3831–3835