Yoosaf, K; Dr. George Thomas, K(Chemical Sciences and Technology Division,CSIR, January , 2008)
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Abstract:
Most of the procedures reported for the synthesis of metal
nanoparticles involve the use of strong reducing agents or elevated
temperatures. This limits the possibility of developing metal nanoparticle
based sensors for the in situ detection of analytes. One of the objectives of
the present investigations is to (i) develop newer methodologies for the
synthesis of metal nanoparticles in aqueous medium at ambient conditions
and (ii) their use in the detection of metal cations by taking advantage of
the unique coordination ability. Ideally, biocompatible molecules which
possess both the reducing and stabilizing groups are desirable for such
applications. Formation of stable supramolecular assembly, by bringing metal nanoparticles close to each other, results in plasmon coupling and
this strategy can be effectively utilized for the development of metal
nanoparticle based sensors.Another objective of the present study is to understand the
supramolecular organization of molecules on surfaces. Various
noncovalent interactions between the molecules and with surface play a
decisive role in their organizations. An in-depth understanding of these
interactions is essential for device fabrications. Recent photophysical
studies have revealed that phenyleneethynylene based molecular systems
are ideal for device application. The second objective of the thesis focuses
on understanding the (i) organization of phenyleneethynylenes on highly
oriented pyrolytic graphite (HOPG) surface with atomic level precision and
(ii) weak intermolecular interactions which drive their organization.