title: Nanometal Skin of Plasmonic Heterostructures for Highly Efficient Near-Field Scattering Probes.
abstract: In this work, atomic force microscopy probes are functionalized by virtue of self-assembling monolayers of block copolymer (BCP) micelles loaded either with clusters of silver nanoparticles or bimetallic heterostructures consisting of mixed species of silver and gold nanoparticles. The resulting self-organized patterns allow coating the tips with a sort of nanometal skin made of geometrically confined nanoislands. This approach favors the reproducible engineering and tuning of the plasmonic properties of the resulting structured tip by varying the nanometal loading of the micelles. The newly conceived tips are applied for experiments of tip-enhanced Raman scattering (TERS) spectroscopy and scattering-type scanning near-field optical microscopy (s-SNOM). TERS and s-SNOM probe characterizations on several standard Raman analytes and patterned nanostructures demonstrate excellent enhancement factor with the possibility of fast scanning and spatial resolution <12 nm. In fact, each metal nanoisland consists of a multiscale heterostructure that favors large scattering and near-field amplification. Then, we verify the tips to allow challenging nongap-TER spectroscopy on thick biosamples. Our approach introduces a synergistic chemical functionalization of the tips for versatile inclusion and delivery of plasmonic nanoparticles at the tip apex, which may promote the tuning of the plasmonic properties, a large enhancement, and the possibility of adding new degrees of freedom for tip functionalization.
authors: University of Naples Federico II, Dept. of Physics E. Pancini, via Cintia 80126-I, Naples, Italy.
authors: Gianluigi
authors: G
authors: Zito
authors: University of Naples Federico II, Dept. of Physics E. Pancini, via Cintia 80126-I, Naples, Italy.|Istituto Nazionale di Ottica (INO) Consiglio Nazionale delle Ricerche, via Campi Flegrei 34- 80078 Pozzuoli, Italy.
authors: Giulia
authors: G
authors: Rusciano
authors: Istituto SPIN U.O.S. Consiglio Nazionale delle Ricerche, via Giovanni Paolo II 132, 84084, Fisciano, Italy.|University of Salerno, Dept. of Physics, via Giovanni Paolo II 132, 84084, Fisciano, Italy.
authors: Antonio
authors: A
authors: Vecchione
authors: University of Naples Federico II, Dept. of Physics E. Pancini, via Cintia 80126-I, Naples, Italy.
authors: Giuseppe
authors: G
authors: Pesce
authors: University of Naples Federico II, Dept. of Chemical Sciences, via Cintia 80126-I, Napoli, Italy.
authors: Rocco
authors: R
authors: Di Girolamo
authors: University of Naples Federico II, Dept. of Chemical Sciences, via Cintia 80126-I, Napoli, Italy.
authors: Anna
authors: A
authors: Malafronte
authors: University of Naples Federico II, Dept. of Physics E. Pancini, via Cintia 80126-I, Naples, Italy.|Istituto Nazionale di Ottica (INO) Consiglio Nazionale delle Ricerche, via Campi Flegrei 34- 80078 Pozzuoli, Italy.
authors: Antonio
authors: A
authors: Sasso