http://hdl.handle.net/2289/147 Search the Channel search http://dspace.rri.res.in:8080/jspui/simple-search http://hdl.handle.net/2289/5594 Title: Thiophene-based donor–acceptor conjugated polymer as potential optoelectronic and photonic material<br/><br/>Authors: Murali, M.G.; Udayakumar, D.; Yadav, Vandana; Srivastava, Ritu; Safakath, K.<br/><br/>Abstract: In this paper, we report the synthesis, characterization and optical properties of a donor–acceptor conjugated polymer, PTh-CN, containing 3,4-didodecyloxythiophene and cyanovinylene units. The polymer possesses a low band gap of 1.75 eV as calculated from the onset absorption edge. From the electrochemical study, the HOMO and LUMO energy levels of the polymer are figured out to be −5.52 eV and −3.52 eV, respectively. Polymer light-emitting diodes are fabricated using PTh-CN as the emissive layer with a device configuration of ITO/PEDOT:PSS/PTh-CN/Al. The device showed stable saturated red electroluminescence with CIE coordinate values (0.65, 0.32) at 12 V, which are very close to the values for standard red demanded by the NTSC. In addition, the device showed good colour stability under different bias voltages and the threshold voltage of the PLED device is found to be as low as 3.1 V. Further, a nanocomposite of the polymer and TiO2 nanoparticles is prepared by the dispersion method. The nonlinear optical properties of PTh-CN and PTh-CN/TiO 2 nanocomposite are studied using z-scan technique. The polymer solution, polymer film and polymer/TiO2 nanocomposite film show a strong saturable absorption behaviour. The value of saturation intensity (Is) is found to be of the order 1011–1012 W/m2, indicating that the materials are useful candidates for photonic applications.<br/><br/>Description: Open Access http://hdl.handle.net/2289/5585 Title: Atom cavity interactions with hot and cold atomic vapors<br/><br/>Authors: Sharma, Arijit http://hdl.handle.net/2289/5584 Title: Trapping and cooling of Ions and the study of Ion atom interactions<br/><br/>Authors: Krishnamurthy, Ravi http://hdl.handle.net/2289/5583 Title: Size-dependent optical properties of Au nanorods<br/><br/>Authors: Smitha, S.L.; Gopchandran, K. G.; Smijesh, N.; Philip, Reji.<br/><br/>Abstract: In the fast evolving field of nanoscience and nanotechnology, where size and shape are crucial in deciding the optoelectronic properties of nanomaterials, the understanding of size and shape dependent behavior is of direct relevance to device applications. Present study reports the synthesis of Au nanorods with well controlled aspect ratios, and the influence of the aspect ratio on the surface enhanced Raman scattering (SERS) activity using crystal violet (CV) as the probe molecule. The influence of pH and the concentrations of reducing agent and Ag ions in controlling the aspect ratio of gold nanorods are also investigated. The structural and optical properties of the synthesized samples have been characterized by transmission electron microscopy (TEM) and UV–visible absorption spectroscopy. The nonlinear optical (NLO) transmission of the Au nanorods investigated using the open aperture Z-scan technique revealed the absorption saturation followed by an optical limiting behavior, which may find potential applications in optoelectronic nanodevices.<br/><br/>Description: Restricted Access.