RESUMEN
The direct covalent attachment of conducting polymers (CP) to nanoparticles (NP) to form CP-NP nanohybrids is of great interest for optoelectronic device applications. Hybrids formed by covalently anchoring CP to NP, rather than traditional blending or bilayer approaches, is highly desirable. CP-NP nanohybrids have increased interfacial surface area between the two components, facilitating rapid exciton diffusion at the p-n heterojunction. These materials take advantage of the facile solution processability, lightweight characteristics, flexibility, and mechanical strength associated with CPs, and the broad spectral absorption, photostability, and high charge carrier mobility of NPs. We demonstrate the ability to polymerize a hole transporting (HT) polymer utilizing reversible-addition-fragmentation chain transfer (RAFT) polymerization and its subsequent rapid aminolysis to yield a thiol-terminated HT polymer. Subsequent facile attachment to gold (Au) and silver (Ag) NPs and cadmium selenide (CdSe) quantum dots (QDs), to form a number of CP-NP systems is demonstrated and characterized. CP-NP nanohybrids show broad spectral absorptions ranging from UV through visible to the near IR, and their facile synthesis and purification could allow for large scale industrial applications.
RESUMEN
The capability of cucurbit[n]uril to align gold nanorods, leading to optical coupling into the infrared region, is shown. Cryo-TEM and tomographic imaging confirm the presence of aligned Au nanorods. Full electromagnetic simulations, which support the observed plasmonic modes and predict large enhancements in the inter-particle junction, are performed. This construct is then further utilized for surface enhanced Raman spectroscopy.
RESUMEN
Late transition metal nanoparticles (NPs) with a favorably high surface area to volume ratio have garnered much interest for catalytic applications. Yet, these NPs are prone to aggregation in solution, which has been mitigated through attachment of surface ligands, additives or supports; unfortunately, protective ligands can severely reduce the effective surface area on the NPs available for catalyzing chemical transformations. The preparation of 'metastable' NPs can readily address these challenges. We report herein the first synthesis of monodisperse metastable ruthenium nanoparticles (RuNPs), having sub 5 nm size and an fcc structure, in aqueous media at room temperature, which can be stored for a period of at least 8 months. The RuNPs can subsequently be used for the catalytic, quantitative hydrolysis of ammonia-borane (AB) yielding hydrogen gas with 21.8 turnovers per min at 25 °C. The high surface area available for hydrolysis of AB on the metastable RuNPs translated to an Ea of 27.5 kJ mol(-1) , which is notably lower than previously reported values for RuNP based catalysts.