________________________________________ Available online at www.sadgurupublications.com * Author for correspondence; E-mail: priteepawar@yahoo.in, sandeepwaghuley@sgbau.ac.in Sci. Revs. Chem. Commun.: 2(3), 2012, 419-422 ISSN 2277-2669 OPTICAL PROPERTIES OF SINGLE STEP SYNTHESIZED NANOSTRUCTURED BISMUTH OXIDE USING HYPERBOLIC BAND MODEL P. A. PAWAR, K. R. NEMADE and S. A. WAGHULEY * Department of Physics, Sant Gadge Baba Amravati University, AMRAVATI – 444602 (M.S.) India (Received : 21.02.2012; Revised : 15.03.2012; Accepted : 21.03.2012) ABSTRACT The nanostructured bismuth oxide (Bi 2 O 3 ) was synthesized by chemical method with different concentration of HMT at room temperature. The particle size dependence of Bi 2 O 3 on HMT was studied from UV-VIS spectroscopy. Optical band gap analysis of synthesized material was studied using hyperbolic band model. With the same model particle size of synthesized materials were also computed. Key words: Optical properties, Bismuth oxide, Hyperbolic band model INTRODUCTION Nanocrystalline particles generally display properties different from their bulk counterparts from which they are derived. Due to their unique physical and chemical properties, bismuth oxide nanoparticles have been used widely as an important component in the field of solid oxide fuel cells, gas sensors, varistors, electric and optical materials, high temperature superconductor materials, functional ceramics and catalysts, etc. 1,2 . Bismuth oxide (Bi 2 O 3 ) is used in a variety of areas, such as sensor technology, optical coatings and electrochromic materials 3,4 , due to its high refractive index, dielectric permittivity, marked photoconductivity and photoluminescence 5 . Bismuth trioxide nanoparticles are widely used in various applications such as electronics and catalytic materials due to their high oxygen-ion conductivity and selective oxidation of hydrocarbons 6,7 . Recently, α-Bi 2 O 3 bismuth trioxide has found extensive applications as an oxidizing component in nanoenergetic materials (NMs) or metastable intermolecular composites (MIC) 8,9 . High purity bismuth nitrate, Bi(NO 3 ) 3 .5H 2 O, was used as the oxidizer. Bismuth oxide as a component finds use in wide applications in varistors, catalyst and gas sensors. Bismuth oxide (Bi 2 O 3 )-based compounds are much better solid electrolytes than well-known stabilized zirconia, because the face-centred cubic (FCC) Bi 2 O 3 exhibits the highest ion conductivity of all oxide ion conductors 10,11 . Bi 2 O 3 is also used as an additive in paints. These special features explain the great effort devoted to the investigation of Bi 2 O 3 polymorphs over the past few years. Bi 2 O 3 has five main polymorphic forms, denoted by α-, β-, γ-, δ- and ω- Bi 2 O 3 12,13 . Among them, the band gaps of the low-temperature α-phase and high-temperature metastable β- phase are 2.85 eV and 2.58 eV, respectively 14 .