Research

Optical Sensing for environmental monitoring & smart packaging.

Polymer-based planar photonic crystals are designed for label-free detection of pollutants, offering a significant advancement over existing technologies for air and water quality assessment. These sensors achieve label-free selectivity by leveraging the distinct intercalation kinetics of analytes within the polymer matrix, governed by polymer-analyte physicochemical interactions, as described by the Flory-Huggins parameters. This mechanism enables the differentiation of analytes without the need for chemical labels. The versatility of these sensors makes them suitable for applications in industrial and environmental monitoring, as well as in food packaging.

Molecular diffusion in thin films:

Simple UV-Vis optical spectroscopy enables the monitoring of small molecule diffusion in polymer thin films. By analyzing the kinetics of the optical response during sorption and desorption processes, this technique provides a novel method for assessing molecular diffusion coefficients in both polymer and porous inorganic matrices. Recent studies have demonstrated that this approach can also be applied to commercial thin films used in food packaging systems.

Polymer photonics for the control of emission and lasing:

Historically, inorganic photonic structures have been utilized to manipulate light for applications such as emission enhancement, lasing, optical switching, and photon recycling in photovoltaic devices. While inorganic materials offer exceptional performance due to their high dielectric contrast, their fabrication is often expensive and time-consuming.

This research aims to demonstrate that solution-processable polymers and hybrid materials can serve as viable alternatives to inorganic media in photonic applications. To achieve this, various commercial and synthetic polymers can be exploited to demonstrate their suitability for emission enhancement and lasing in combination with conjugated polymers, inorganic nanocrystals, J-aggregates, and perovskite emitters.

Photon Harvesting enhancement in Photocatalytic Systems

hen a photoactive medium is integrated into a dielectric lattice, light absorption can be significantly enhanced at the stop-band edges due to (i) light confinement and (ii) the generation of slow photons, which propagate with reduced group velocity, leading to extended lifetimes and stronger interactions with the medium.

This research focuses on the design and fabrication of photoactive Bragg stacks composed of oxide semiconductors, processed under mild solution-based conditions. The objective is to demonstrate slow photon enhancement in water remediation and other photocatalytic applications.

Sol-gel synthesis of inorganic photoactive media

This project target new one-pot synthetic procedures for the fabrication of inorganic porous media for photo-oxidative and photo-reductive processes. The goal is to achieve spectral absorbance broadening compared to standard wide-bandgap semiconductor oxides, by leveraging metal oxide alloys and doping with plasmonic nanoparticles synthesized specifically for this purpose.

Chemical processes and syntheses:

Engineering new structures often requires materials that are not available commercially. To this end, several active media are engineered and/or synthesized ad-hoc, and their processability is investigated. A large work is focused on the synthesis of polymer-inorganic hybrids to control permeability and refractive index and on the solution processing of fully-inorganic structures.

Thermal Shielding

Year by year, the importance of thermal shielding as a passive method of cooling has seen an increase in its importance in several applications. This includes, for instance, reduction of energetic consumption in vehicles and buildings, and conservation of foods and beverages along the production, transportation and storage chain. Photonic Crystals can be efficient reflectors for near-infrared radiation, the spectral region responsible for about half of the radiative heating caused by sunlight.

Light Harvesting Enhancement in Photovoltaics and Photocatalysis

Light harvesting in photoactive species can be enhanced with a variety of strategies and structures, including self-assembly scatters and diffraction systems, modification of the local density of photonic states and control of photon propagation velocity. The group has a consolidated background in the field applied to solar concentrators and is now working in photocatalytic system for air and water remediation.

Polymer and Solution processed Metamaterials

Metamaterials are artificial structures where properties are defined by the architecture rather than by composition. In general, metamaterials for photonics need downsizing at about 10 nm generating a local structure - the meta-atom - responsible for the overall properties. In this way, light-matter interactions can be controlled creating exotic effects such as negative refraction, generating hot-spots where light-matter interaction is enhanced.

Rely-photonics aims to make macromolecules active key-elements of metamaterials exploiting the ease of chemical engineering of their electronic response, which controls their refractive index, which is commonly too low for metamaterials. To this aim, the group is exploiting its consolidated background in the engineering of the optical properties of polymers to obtain proof-of-concepts elements, which are the cornerstone of modern photonics and optical signal handling, namely second harmonic generators (SHGs) and radiative rate modifier to create a new generation of more efficient and less energy consuming photonic elements.