arXiv subjects

Fabio Marangi

Publications and source records attributed to Fabio Marangi.

6 recordsLinked to original sources

arXiv2026

Tamm Plasmon Resonance Responsiveness to SARS-CoV-2 Virus-Like Particles

Bioresponsive optical materials that transduce nanoscale biointerface events into measurable spectral signals are of growing interest for sensing and antiviral technologies Here we show that a Tamm plasmon TP device consisting of a SiOTiO distributed Bragg reflector capped with a nanostructured silver layer exhibits a selective and structure dependent response to SARSCoV2 virus like particles VLPs Upon VLP exposure the conventional wavelength shift delta lambda of the TP resonance is minimal whereas the resonance depth undergoes a systematic attenuation To capture both spectral and amplitude variations we introduce a displacement angle alpha defined from the translation vector of the Tamm dip before and after exposure The angle alpha increases monotonically with VLP concentration and enables a limit of detection of 13 ng per mL Control experiments with polystyrene nanoparticles of similar size and with heat denatured VLPs yield negligible changes indicating sensitivity to the native conformational state of viral surface proteins rather than to generic nanoparticle morphology or bulk refractive index effects These results establish Tamm plasmon structures as promising bioresponsive platforms for label free detection and for probing structure dependent virus material interactions.

physics.optics↗

arXiv2023

Role of the annealing parameters on the resistance of indium tin oxide nanocrystalline films

The optical and electrical properties of films made of nanoparticles of indium tin oxide (ITO) are widely studied because of the significance of this material for transparent electrodes, smart windows, and nonlinear optics components. In this work, a systematic study of the resistance in ITO nanocrystalline films, as a function of post-fabrication parameters, such as the temperature and time of annealing, has been performed. A tunability of the resistance with the annealing parameters, in a range of three orders of magnitude, has been demonstrated.

cond-mat.mes-hall↗

arXiv2022

Tamm Plasmon Resonance as Optical Fingerprint of Silver/Bacteria Interaction

Incorporation of responsive elements into photonic crystals is an effective strategy for building up active optical components to be used as sensors, actuators and modulators. In these regards, Tamm Plasmon (TP) modes have arisen recently as powerful optical tools for the manipulation of light-matter interaction and for building sensors/actuators. These emerge at the interface between a dielectric mirror and a plasmonic layer and, interestingly, can be excited at normal incidence angle with relatively high quality factors. Although its field is located at the interface between the dielectric mirror and the metal, recent studies have demonstrated that corrugation at the nanoscale permits to access the TP mode from the outside, opening new exciting perspectives for many real-life applications. Here, we show that the TP resonance obtained by capping a distributed Bragg reflector with a nanostructured layer of silver is sensitive to the presence of bacteria. We observed that nanoscale corrugation is essential for accessing the TP field, while the well-known bio-responsivity of silver nanostructures renders such a localised mode sensible to the presence of Escherichia Coli. Electrodoping experiments confirm the pivotal role of nanostructuration, as well as strengthening our hypothesis that the modifications of the TP mode upon exposure to bacteria are related to the accumulation of negative charge due to the bacterial-driven removal of Ag+ ions from its lattice. Finally, we devised a case study in which we disentangled optically the presence of proliferative and non-proliferative bacteria using the TP resonance as a read-out, thus making these devices as promising simple all-optical probes for bacterial metabolic activity, including their response against drugs and antibiotics.

physics.optics↗

arXiv2022

Near-Infrared plasmon induced hot electron extraction evidence in an indium tin oxide nanoparticle / monolayer molybdenum disulphide heterostructure

In this work, we observe plasmon induced hot electron extraction in a heterojunction between indium tin oxide nanocrystals and monolayer molybdenum disulphide. We study the sample with ultrafast differential transmission exciting the sample at 1750 nm where the intense localized plasmon surface resonance of the indium tin oxide nanocrystals is and where the monolayer molybdenum disulphide does not absorb light. With the excitation at 1750 nm we observe the excitonic features of molybdenum disulphide in the visible range, close to the exciton of molybdenum disulphide. Such phenomenon can be ascribed to a charge transfer between indium tin oxide nanocrystals and monolayer molybdenum disulphide upon plasmon excitation. These results are a first step towards the implementation of near infrared plasmonic materials for photoconversion.

physics.optics↗

arXiv2021

New Strategies for Solar Cells Beyond the Visible Spectral Range

The endeavor of the scientific community to maximize the possibility to harvest Sun irradiation for energy production is mainly devoted to the improvement of the power conversion efficiency of devices and to the extension of the spectral range in which solar devices operate. Considering that a significant portion of the Sun irradiation at the ground level is in the infrared, the research on materials and systems that operate in such region is gaining increasing attention. In this review, we will report recent advancements in multijunction solar cells, inorganic-organic perovskite solar cells, organic solar cells, colloidal quantum dot solar cells focusing on the absorption of such devices in the infrared. In addition, the use of upconverting nanostructures will be introduced as a way to indirectly exploit infrared radiation to increase power conversion efficiency of photovoltaic devices. Moreover, we will describe plasmon induced hot electron extraction based solar cells, that are particularly promising in absorbing the infrared portion of the Sun irradiation when the active materials are doped semiconductors, which show intense plasmonic resonances in the infrared. The review includes the optical spectroscopy tools to study the hot electron extraction from doped semiconductor-based heterojunctions.

cond-mat.mes-hall↗

arXiv2020

Electrochromism in Electrolyte-Free and Solution Processed Bragg Stacks

Achieving an active manipulation of colours has huge implications in optoelectronics, as colours engineering can be exploited in a number of applications, ranging from display to lightning. In the last decade, the synergy of the highly pure colours of 1D photonic crystals, also known as Bragg stacks, with electro-tunable materials have been proposed as an interesting route to attain such a technologically relevant effect. However, recent works rely on the use of liquid electrolytes, which can pose issues in terms of chemical and environmental stability. Here, we report on the proof-of-concept of an electrolyte free and solution-processed electrochromic Bragg stack. We integrate an electro-responsive plasmonic metal oxide, namely indium tin oxide, in a 1D photonic crystal structure made of alternating layers of ITO and TiO2 nanoparticles. In such a device we observed 15 nm blue-shift upon application of an external bias (5 V), an effect that we attribute to the increase of ITO charge density arising from the capacitive charging at the metal oxide/dielectric interface and from the current flowing throughout the porous structure. Our data suggest that electrochromism can be attained in all-solid state systems by combining a judicious selection of the constituent materials with device architecture optimisation.

physics.app-ph↗