11 Synthesis and Crystal Growth of Sb 2 S 3 Nanorods Using Iodine as an Initiator Material via Electrochemical Mechanism in Hydrothermal Condition A. Alemi * , Y. Hanifehpour Firouzsalari Department of Inorganic Chemistry, Faculty of Chemistry, University ofTabriz, I. R. Iran (*) Corresponding author: alemi.aa@gmail.com (Received: 15 Dec. 2011 and Accepted: 25 Feb. 2012) Abstract: Crystalline antimony sulfide (Sb 2 S 3 ) with nanorods morphology was successfully prepared via hydrothermal method by the reaction of elemental sulfur, antimony and iodine as starting materials with high yield at 180°C for 24h.Using oxidation reagents like iodine as an initiator of redox reaction to prepare Sb 2 S 3 is reported for first time. Crystal growth of Sb 2 S 3 was done by increasing reaction time up to 3 days. The powder X-ray diffraction pattern shows the Sb 2 S 3 crystals belong to the orthorhombic phase with calculated lattice parameters of a=1.120nm, b=1.128nm and c=0.383nm. The quantification of energy dispersive X-ray spectrometry analysis peaks give an atomic ratio of 2:3 for Sb:S. Scanning electron microscopy (SEM) images show that the diameter of nanorods was around 250-380 nm and their length was less than 3 µm, respectively. After crystal growth due to increasing the reaction time, diameter of nanorods was reached to about 500-700 nm and their length extended to about 6 µm. UV-Vis analysis and emission spectra indicates that band gap of Sb 2 S 3 is around 2.82eV, indicating a considerable blue shift relative to the bulk. Moreover, formation mechanism of Sb 2 S 3 nano structure was proposed and the effect of reaction time on the growth of nano materials was also investigated. Keywords: Antimony sulfide, Nanorods, Crystal growth, Red-ox reaction, Hydrothermal. Int. J. Nanosci. Nanotechnol., Vol. 8, No. 1, March 2012, pp. 11-18 1. INTRODUCTION Antimony sulfide, a layer-structured direct band gap semiconductor with orthorhombic crystal structure, is an important semiconductor with high photo sensitivity and high thermoelectric power [1]. In the past few years, main group metal chalcogenides such as A 2 B 3 (where A=As,Sb,Bi and B=S,Se,Te) as significant semiconductors have received ever increasing attention[2]. Due to its good photo conductivity, Sb 2 S 3 has received significant attention for potential application in solar energy conversion [3]. It has also been used in switching devices [4], thermoelectric cooling technologies, optoelectronics in the IR region [5- 6], and microwave devices [7], television cameras [8]. Sb 2 S 3 exist in two forms: orange amorphous phase and black orthorhombic modification with a ribbon like polymeric structure along the [001] direction as the building blocks [9]. Each Sb atom and each S atom is bond to three atoms of the opposite kind within the ribbon-like polymeric structure, forming interlocking SbS 3 and SSb 3 pyramids. Consequently, amorphous Sb 2 S 3 tends to crystallize into one dimensional shape to support the stronger