Assistant Professor,
Ruthenium, Osmium, Rhodium, Iridium, Platinum and Palladium which form part of the transition metals are more collectively called platinum metals. Their synthesis/fabrication at nano level in various forms and study of these nano -sized Ms. Materials are of immense importance. Some of the simple compounds of these metals at nano level have the potentials of exhibiting some new properties. Some valuable work in this direction has been carried out and this field needs to be explored more. The purpose of this study is to explore the possibilities of synthesis of such nano sized particles by chemical and electrochemical methods which are more accessible to every person interested in research in this area.
Nanometer is one millionth of a millimeter i.e 10-9 meter. Materials falling in this range- 1-100nm, more specifically, are known as nano materials. Elements at nano scale exhibit changed/improved behavior. Gold changes its state from solid to liquid & can be converted into many colours. Carbon nanotube is about 100 times stronger & six times lighter than steel, Silicon at nano level becomes good conductor. Aluminium becomes combustible, copper transparent & platinum becomes catalyst. Changed properties of nano sized materials have been ascribed to the increased surface area & the quantum effects that intervene at such a small scale. New optical properties are exhibited by nano particle because of confinement effects & the colour of quantum dots is dictated by confinement phenomenon & particle localization. Quantum dots are three dimensionally confined nanoparticles with semiconducting properties. Two new developments, in semiconductors, take place when electrons are restricted to very small region. First, HOMO-LUMO energy gap increases & second the energy levels of electrons are quantized. Quantum confinement also reduces the linear momentum to minimum & therefore, transitions do not require any momentum. Coherent oscillations occur at the interface of a metal with a dielectric medium which are called Plasmons. To excite colours from bulk metals the momenta of the Plasmons & photons must match. In nanoparticles the surface plasmons are localized & have no characteristic momenta & the momenta of plasmons & the photons do not need to match & the excitation of plasmons occur with greater intensity. The nature of the metal, the dielectric surrounding, size & shape of the nanoparticles are the guiding factors for Plasmon absorption.
