Browsing by Subject "optoelectronic device fabrication"

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    Investigating the Effects of Size and Shape of Anisotropic Nanostructures on the Molecular Sensor Response
    (Office of the Vice Chancellor for Research, 2014-04-11) Ekoma, Sandra; Joshi, Gayatri K.; Sardar, Rajesh
    The photoreversiblity of molecular machine-attached onto anisotropic nanostructures have been studied using optical spectroscopy. For the first time, we have observed an unprecedented 21-nm shift of localized surface plasmon resonance (LSPR) peak of gold nanoprism upon cis to trans isomerization of azobenzenes. The observed shift was a combined effect of energy transfer across the nanostructure and azobenzene molecule and increase in the dielectric environment of the nanostructure. Furthermore, we also investigated the geometrical effects of plasmonic nanostructures by fine-tuning their size and shape on sensitivity of molecular sensors and determined the mechanism underlying LSPR peak shifts. Understanding such mechanism will aid in designing highly efficient sensing platforms for future optoelectronic device fabrication.
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    Pure white‐light emitting ultrasmall organic‐inorganic hybrid perovskite nanoclusters
    (RSC, 2016-10) Teunis, Meghan B.; Lawrence, Katie N.; Dutta, Poulami; Siegel, Amanda P.; Sardar, Rajesh; Department of Chemistry & Chemical Biology, School of Science
    Organic–inorganic hybrid perovskites, direct band-gap semiconductors, have shown tremendous promise for optoelectronic device fabrication. We report the first colloidal synthetic approach to prepare ultrasmall (∼1.5 nm diameter), white-light emitting, organic–inorganic hybrid perovskite nanoclusters. The nearly pure white-light emitting ultrasmall nanoclusters were obtained by selectively manipulating the surface chemistry (passivating ligands and surface trap-states) and controlled substitution of halide ions. The nanoclusters displayed a combination of band-edge and broadband photoluminescence properties, covering a major part of the visible region of the solar spectrum with unprecedentedly large quantum yields of ∼12% and photoluminescence lifetime of ∼20 ns. The intrinsic white-light emission of perovskite nanoclusters makes them ideal and low cost hybrid nanomaterials for solid-state lighting applications.