No abstract

No abstract

In this work, we present a novel method to produce thermoresponsive, monodisperse microgels which display temperature-dependent photoluminescence. The system is based on bimetallic cores of Au@Ag encapsulated within thermoresponsive poly(N-isopropylacrylamide) microgels and coated with a photoluminescent polymer (poly[2-(3-thienyl)ethoxy-4-butylsulfonate] (PTEBS) using the Layer-by-Layer technique. The electromagnetic radiation used to excite the PTEBS induces a local electromagnetic field on the surface of the bimetallic cores that enhances the excitation and emission rates of the PTEBS, yielding a metal enhanced fluorescence (MEF). This effect was studied as a function of the bimetallic core size and the separation distance between the PTEBS and the bimetallic cores. Our results permit evaluation of the effect that the metallic core size of colloidal particles exerts on the MEF for the first time, and prove the relevance of the metallic cores to extend the effect far away from the metallic surface.

Two novel ruthenium complexes are synthesized and used as photosensitizers in dyesensitized solar cells (DSCs): [RuCl2(mPTA)3(H2O)](CF3SO3)3 (C1) (m: methyl; PTA: 3,5,7-triazaphosphaadamantane) and [Ru(C=C=CPh2)Cp(PTA)(PPh3)](CF3SO3) (C2). The complexes are soluble in organic solvents and, interestingly, in water, which makes them useful for water-based photochemical processes. They possess excellent photon-absorption properties over a wide range of the UV-vis spectrum with intense peaks at ~ 330 nm for both sensitizers and a second peak for C2 at 525 nm, much stronger than the corresponding to dye N719. The performance of DSCs containing these sensitizers are evaluated using different electrolytes in comparison with a reference cell made with N719. The solar cell performance was similar for both complexes and strongly dependent on the electrolyte, with a maximum conversion efficiency of 0.33 % for the iodide/triiodide electrolyte. In spite of presenting low efficiencies, these novel ruthenium dyes produce electricity from light effectively and are highly stable under irradiation conditions.