The National Metrology Institute of India and A Premier Research Laboratory in the Field of Physical Sciences
Electrochromic, Nanostructured and Polymeric thinfilms & Devices and Surface physics.

Surface Studies and Nanostructures

Under the Surface Studies and Nanostructures activity, the formation of antimony 1D structures on Si (5 5 12) surface was studied. Adsorption of antinomy metal on high index Si (5 5 12) which is composed of (2 2 5) and (3 3 7) regions with nanoscale widths and row like trenches and provides an unique template for the growth of nanostructures was studied. Various superstructural phases were formed by steering the kinetic parameters and post growth annealing of the surface

Studies in Conducting Polymers

Under Studies in Conducting Polymers, the chemistry of chemical doping in conjugated polymers has been studied. An evidence for disruption in pconjugation upon increase in doping was established through various photo-physical, electrical and morphological investigations. The dielectric constant ε′(ω), dielectric loss ε′′(ω)and ac conductivity σ(ω)m of lightly doped poly (3-hexylthiophene) (P3HT) films give the evidence that, both dc conductivity as well as dielectric relaxation originate from the same hopping process.

Hybrid Organic - Inorganic Nanocomposites

Under the Hybrid Organic-Inorganic Nanocomposites activity, CdSe nanocrystals (6-10 nm) prepared by chemical route using TOP/ TOPO capping were dispersed in conducting PPV (p-phenylenevinylene) and P3HT (3-hexylthiophene) polymer matrices using a binary solvent mixture (pyridine-chloroform) respectively and tailored by altering the composition and concentration of NC’s in CP. Stern-Volmer plots indicate heterogeneous quenching of PL emission for smaller CdSe quantum dots ensuring efficient charge transfer process across polymer-CdSe interface.

Under the Synthesis of Nanocrystalline Metal Oxides for Gas Sensors

Under the Synthesis of Nanocrystalline Metal Oxides for Gas Sensors activity, nanocrystalline / mesoporous tin oxide powders were prepared using chemical techniques. The gas sensitivity of the derived sensors were investigated for various gases ethanol, acetone, TMA, DMA, ammonia, NOx, CO, LPG and CNG. SnO2 powder was prepared by precipitation route. Ammonia and NOx sensors are desired for environmental monitoring and food freshness monitoring. A systematic study was made to improve ammonia and NOx sensitivity using doped (Pt, Au, Pd) WO3 as sensitive material.

In the Electrochromic Materials and Devices

In the Electrochromic Materials and Devices activity, the unequalled potential of aqueous micellar chemistry for synthesizing nanostructured electroactive polymer films of high cosmetic quality has been demonstrated by the remarkably high electrochromic coloring efficiency, fast color-bleach speeds and outstanding durability shown by of poly (3, 4 - ethylenedioxythiophene) films and prototype electrochromic windows processed by this method.