Davide Comoretto

Università degli Studi di Genova | UNIGE · Department of Chemistry and Industrial Chemistry

Optical microcavities grant manipulation over light-matter interactions and light propagation, enabling the fabrication of foundational optical and optoelectronic components. However, the materials used for high-performing systems, mostly bulk inorganics, are typically costly, and their processing is hardly scalable. In this work, we present an alt...

Nowadays, consumers can estimate the condition of packaged foods only by checking the expiration date on the label. However, this approach is inefficient when it comes to assessing the actual edibility of fresh products, since the events that accelerate the onset of degradation phenomena, such as a rise in temperature, cannot be continuously assess...

An experimental method exploiting the capacitive response of most materials is here revised. The procedure called the “Voltage Ramp Method” (VRM) is based on applying proper voltage ramp cycles over time and measuring electrical current intensity flowing through the material sample. In the case of an ideal capacitor, a current plateau should be eas...

Controlling the radiative rate of emitters with macromolecular photonic structures promises flexible devices with enhanced performances that are easy to scale up. For instance, radiative rate enhancement empowers low-threshold lasers, while rate suppression affects recombination in photovoltaic and photochemical processes. However, claims of the Pu...

Solution processing of highly performing photonic crystals has been a towering ambition for making them technologically relevant in applications requiring mass and large-area production. It would indeed represent a paradigm changer for the fabrication of sensors and for light management nanostructures meant for photonics and advanced photocatalytic...

A novel thiophene derivative, namely 2,5-diisopropenylthiophene (DIT) was synthetized by Suzuki-Miyaura cross-coupling reaction (SMCCR). The influence of reaction parameters, such as temperature, solvent, stoichiometry of reagents, role of the base and reaction medium were thoroughly discussed in view of yield optimization and environmental impact...

Preventing solar heating is nowadays of paramount interest in energy savings and health preservation. For instance, in building thermalization solar heating consumes an excess of energy leading to harmful CO2 emissions, while in food and beverage packaging it may lead to variation of organoleptic properties or even health issues. The phenomenon is...

The control of radiative decay rate is a crucial issue both for fundamental studies in quantum electrodynamics and for the development of efficient lasers, light emitting devices and photovoltaic cells....

Microcavities are a class of optical structures providing a versatile approach to engineering light matter interactions. In light of recent developments in materials processing technologies, in particular for organic and hybrid ones, and of the need for high efficiency optical systems, there has been extensive innovation and improvement in their de...

In article 2002006, Davide Comoretto and co‐workers demonstrate a one‐dimensional all‐polymer photonic crystal selective to a wide range of chemical species with no need for additional functionalization, promising for portable sensors. Employing the perfluorinated polymer Aquivion with Poly(N‐vinylcarbazole) as building blocks of high refractive in...

Alginate-based electrospun nanofibers prepared via electrospinning technique represent a class of materials with promising applications in the biomedical and pharmaceutical industries. However, to date, the effect of alginate molecular mass and block composition on the biological response of such systems remains to some extent unclear. As such, in...

In article number 2009626, Paola Lova, Davide Comoretto, Heba Megahd propose general guidelines for designing multi‐layered colorimetric vapor sensors using commodity polymers. The response time of the nano‐structured sensors is based on analyte diffusion, which can be controlled through engineering of the number of layers, their thickness, and fre...

A holistic detection system, in principle sensitive to any molecular species in the vapor phase is proposed. The sensor consists of a polymeric multilayered distributed Bragg reflector made of a perfluorinated polar polymer, Aquivion, and a nonpolar polymer, poly(N‐vinylcarbazole). Alternated layers of the two polymers provide a characteristic opti...

Multilayered photonic sensors that rely on polymer‐solvent Flory–Huggins interactions are drawing increasing interest owing to their broad‐band selectivity, even among mixtures, without the need for chemical targeting. Moreover, these sensors provide simple colorimetric responses, and easy, quick fabrication both on laboratory and industrial scales...

Historically, photonic crystals have been made of inorganic high refractive index materials coupled to air voids to maximize the dielectric contrast and in turn the light confinement. However, these systems are complex, costly, and time-demanding, and the fabrication processes are difficult to scale. Polymer structures promise to tackle this issue...

Due to its high toxicity, Pb2+ pollution is a serious threat for human health and environments. However, in situ real-time detection of Pb2+ pollution is difficult and laboratory instruments are usually required. Then, the possibility to monitor water quality without laboratory instruments could lead to the extensive assessment of polluted water so...

Photonic crystals are a unique tool to modify the photoluminescence of light-emitting materials. A variety of optical effects have been demonstrated by infiltrating opaline structures with photoactive media. On the other hand, the fabrication of such structures includes complex infiltration steps, that often affect the opal lattice and decrease the...

Organo-metallic europium complex tetrakis (dibenzoyl methide) triethylammonium (EuD4TEA) shows a sharp emission spectrum, which makes it interesting for photonic applications. In this work, we embedded it into all-polymeric planar microcavities and investigated the effect of the photonic environment on its emission spectrum. To this end, submicron-...

Photonic technologies are nowadays dominated by highly performing inorganic structures that are commonly fabricated via lithography or epitaxial growths. Unfortunately, the fabrication of these systems is costly, time consuming, and does not allow for the growth of large photonic structures. All-polymer photonic crystals could overcome this limitat...

Brilliance usually refers to the light reflected by the facets of a gemstone such as diamond due to its high refractive index. Nowadays, high‐refractive‐index materials find application in many optical and photonic devices and are mostly of inorganic nature. However, these materials are usually obtained by toxic or expensive production processes. H...

Thanks to versatile optoelectronic properties solution processable perovskites have attracted increasing interest as active materials in photovoltaic and light emitting devices. However, the deposition of perovskite thin films necessitates wide range solvents that are incompatible with many other solution-processable media, including polymers that...

The possibility to evaluate the molecular diffusivity in polymer thin films used for packaging and device encapsulation directly in-situ would represent a paradigm changer in the assesment of barrier properties and of air quality. Indeed, employing the packaging itself as a smart sensor could lead to waste reduction and mitigate food poisoning effe...

The possibility to evaluate molecular diffusion coefficient in polymer films directly in-situ is critical to assess barrier properties of packaging systems. Using the polymer packaging itself as smart sensor could lead to increase shelf-life, minimize wastes, and food poisoning effects. In this work we report on a new method that exploit simple UV-...

So far, photonic crystals have been mostly made of high refractive index inorganic materials coupled with air voids to maximize dielectric contrast and enhance light control efficiency. On the other hand, these inorganic structures require costly and time demanding fabrications impossible to scale up on very large area. To this end, polymers could...

The possibility to assess diffusion coefficients of small molecules in packaging polymer films directly on the shelf, or even along the fabrication line, without the use laboratory equipment commonly employed for gravimetric methods would represent a paradigm changer in the evaluation of barrier properties and byproduct formation in goods packaging...

Thanks to solution processability and broad emission in the visible spectral range, 2D hybrid perovskite-like materials are interesting for the realization of large area and flexible lighting devices. However, the deposition of these materials requires broad-spectrum solvents that can easily dissolve most of the commercial polymers and make perovsk...

The lack of cost-effective systems for the assessment of air pollutants is a concern for health and safety in urban and industrial areas. The use of polymer thin-films as label-free colorimetric sensors featuring specific interactions with pollutants would then represent a paradigm shift in environmental monitoring and packaging technologies, allow...

Thanks to high photoluminescence quantum yield, large charge carrier diffusion, and to their ease of processing from solution, perovskite materials are becoming increasingly interesting for flexible optoelectronic devices. However, their deposition requires wide range solvents that are incompatible with many other flexible and solution-processable...

We report on the optical efficiency enhancement of luminescent solar concentrators based on a push-pull fluorophore realized using high dielectric contrast polymer distributed Bragg reflectors as back mirrors. The Bragg stacks are obtained alternating layers of cellulose acetate to thin films of a new stable and solution processable hydrated titani...

Large area surface microstructuring is commonly employed to suppress light reflection and enhance light absorption in silicon photovoltaic devices, photodetectors and image sensors. To date, however, there are no simple means to control the surface roughness of III-V semiconductors by chemical processes similar to the metal assisted chemical etchin...

An overview on the properties and applications of polymer and inorganic planar 1D photonic crystals fabricated from solution is provided here. In the last decades, photonic crystals became technologically relevant for light management, photovoltaics, sensing, and lasing. Such structures are traditionally produced by lithographic and vacuum techniqu...

We report on the highly sensitive optical and colorimetric detection of perfluorinated compounds in the vapor phase achieved by all-polymer dielectric mirrors. High optical quality and uniformly distributed Bragg reflectors were fabricated by alternating thin films of poly(N-vinylcarbazole) and Hyflon AD polymers as high and low refractive index me...

Loading of one-dimensional (1-D) porous silicon photonic crystals (PS-PhCs), known as rugate filters, with luminescent materials is generally limited by the potential for (undesired) “pore clogging,” in relation to the size of the nanoparticles (e.g. quantum dots) or molecular species, and so far mainly restricted to small molecular weight material...

The lack of sensors for continuous and extensive detection of vapor pollutants is a concern for health and safety. Colorimetric sensors, such as polymer distributed Bragg reflectors, could achieve this task thanks to their low cost and easy signal transduction, but are affected by low vapor permeability and lack of selectivity without chemical labe...

Colloidal nanocrystals attract considerable attention in the field of light emitting devices thanks to their high fluorescence quantum yield, low amplified spontaneous emission (ASE) threshold, and spectral tunability via electronic structure engineering and surface functionalization. Combining polymer microcavities with colloidal nanocrystals as g...

Thanks to their broadband emission and solution processability, 2D hybrid perovskite materials are promising for the realization of large area and flexible lighting devices. The deposition of 2D perovskites, however, requires wide range solvents that are incompatible with commodity polymers used for structural support and light management. Here we...

Thanks to exciting chemical and optical features, perylene bisimide J-aggregates are ideal candidates to be employed for high-performance plastic photonic devices. However, they generally tend to form π–π stacked H-aggregates that are unsuitable for implementation in polymer resonant cavities. In this work, the efficient compatibilization of a tail...

Photocatalyzed reactions of 2-(alkoxycarbonyl)benzenediazonium tetrafluoroborates with various alkenes afforded isochromanones in good yields, according to a mechanism that was investigated. The advantage of using highly soluble esters rather than carboxylic acids as starting compounds became evident when the reactions were performed under flow con...

Experimental details and detailed spectroscopic data.

Optical properties of some fluorinated polymers have been described; applications in the framework of Photonics shown and results discussed

We report on the optical and photo-physical properties of a fluorinated poly(p-phenylenevinylene) derivative, namely poly(2-methoxy-5-[(2-ethylhexyl)oxy]-1,4-phenylenedifluorovinylene) (MEH-PPDFV) and we compare them with those of the well-known non fluorinated reference system, poly(2-methoxy-5-[(2-ethylhexyl)oxy]-1,4-phenylenevinylene) (MEH-PPV)...

A flexible way of fabricating core-shell noble metal-organic nanohybrids with tailored chemical and spectroscopic properties is proposed here. The synthetic protocol consists of a multi-step procedure able to guarantee acceptable reproducibility of core size and shape as well as control of the organic outer layer. The proposed method highlights lim...

The lack of sensors for low cost, extensive and continuous detection of vapor pollutants is a serious concern for health and safety in industrialized urban areas. Colorimetric sensors, such as distributed Bragg reflectors made of polymers, could achieve this task thanks to their low cost and easy signal transduction, but are typically affected by l...

For the first time, a multiplanar photonic crystal structure has been obtained using cellulose as a structural material. This all-polymer system, made of cellulose, polyvinyl alcohol and poly(N-vinylcarbazole) is a ternary planar photonic crystal composed by 7 repeated trilayers produced by spin coating. Trimethylsilyl cellulose is used as a precur...

An all-polymer photonic structure constituted by a distributed Bragg reflector topped with an ultrathin fluorescent polymer film has been studied. A Bloch surface wave resonance has been exploited to improve pumping efficiency. A strongly polarization and angle dependent fluorescence signal is found with respect to the light pumping beam and the em...

We report on the Surface Enhanced Raman Scattering (SERS) efficiency of self-organised arrays of Au nanocrescents confined on monolayers of polystyrene nanospheres. A dichroic SERS emission in the visible spectrum is observed due to the selective excitation of a Localised Surface Plasmon (LSP) resonance along the "short axis" of the Au nanocrescent...

We report on the optical photomodulation properties of all-polymer planar microcavities in which the photochromic poly((4-pentyloxy-3’-methyl-4’-(6-methacryloxyhexyloxy))azobenzene) (PMA4) acts as photoresponsive cavity layer. We induce the trans-cis isomerization process of the azobenzene group by polarized 405 nm CW-laser irradiation, while the b...

We report on the growth and characterization of one-dimensional (1D) planar all-polymer photonic crystals (PhC) with high dielectric contrast (Δn = 0.3) prepared by spin coating using hyperbranched polyvinylsulfide polymers (HB-PVS) as high refractive index material and cellulose acetate as low refractive index material. Solution processable HB-PVS...

A multifunctional, semitransparent photovoltaic device is proposed for harvesting sunlight over a tunable spectral range extending from the UV to the IR. Self-assembled monolayers of nanospheres applied to luminescent concentrators provide a photon management architecture, which relies on luminescence and diffraction of light. The light diffraction...

This book provides a multidisciplinary perspective (ranging from chemistry to physics and biology) of the current research and applications of organic and hybrid photonic crystals. The authors detail the chemical and physical tools used to develop organic photonic crystals, explain methods for engineering new nano-structures, and propose novel phys...

Carbon films and coatings are industrially very versatile and have a multiplicity of applications, such as conductive coatings or chemical and thermal protection layers. However, in most cases they are fabricated by the expensive vapor process, which has prevented a wider commercialization of these products. Herein, carbon films are fabricated usin...

We establish a new strategy to achieve fast and responsive hybrid distributed Bragg reflectors for environmental vapor sensing. We fabricated easily processable zinc oxide-polystyrene nanocomposites to grow high quality multilayers with large gas permeability and dielectric contrast, which enable fast and sensitive detection of vapor analytes. Mult...

Polymer multilayer structures have attracted increasing attention in the recent years because of the straightforward and low-cost techniques that can be used for their fabrication. When the multilayers are composed of a periodical alternation of two materials with different refractive indexes and with layer thicknesses comparable with the wavelengt...

We report on ZnO nanoparticles-polystyrene (PS) nanocomposites (NC) engineered to modify PS matrix permeability and refractive index (n), and to fabricate 1D all-polymer photonic crystals (PC) for sensing applications. The new NC can be easily processed from solutions to prepare high quality thin films by spin coating. ZnO nanoparticles (n = 1.98)...

We demonstrate photoluminescence excitation enhancement in an all-polymer flexible one-dimensional photonic crystal structure capped with a fluorescent organic ultrathin film. When optical matching conditions between the excitation beam and the Bloch Surface Wave mode supported by the photonic structure are achieved, a ten times enhancement of the...

We report on an extensive investigation of the anisotropic optical properties of highly oriented poly(p-phenylene vinylene), PPV, a reference material for polymer semiconductors. This system provides a unique opportunity to address the role of intra- and intermolecular interactions by studying the anisotropy of optical and emission properties. Hydr...

The optical quality and photonic properties of all-polymer distributed Bragg reflectors are related to the morphology of the layers and the optical responses of the materials. We introduce the X-ray reflectivity method to determine the thickness, the interface- and surface-roughness of cellulose acetate and polystyrene layers which are two polymers...

A recent theoretical proposal suggested strong coupling between excitons and Bloch Surface Waves, which are photonic modes that exist at the interface between a truncated photonic crystal, and an ideally semi-infinite dielectric medium. In this work we report on the observation of strong coupling between the Bloch surface wave supported by an inorg...

Here we show the way to easily tune and engineer the optical response of hybrid structures composed by self ordered dielectric nanospheres partially covered by anisotropic plasmonic structures. The overall structure is a hybrid plasmonic-photonics nanostructure acting as a meta-surface witch morphology allows efficient and versatile light manipulat...

This work deals with very thin (14-40 nm) films of a polyester containing diarylethene units in the main chain spin cast on a silicon wafer. By irradiation with UV light the colourless form turns blue due to the appearance of a strong absorption band centred at about 600 nm. The coloured state is thermally stable and the backward conversion can be...

We report on the laser action in a microcavity where both the dielectric mirrors and the active material have a macromolecular nature, resulting in a full plastic laser device. Distributed Bragg reflectors (DBRs) are prepared by spin-coating of polyvinylcarbazole and cellulose acetate orthogonal solutions and the active layer consists of a highly f...

Hybrid structures composed by self-ordered dielectric nanospheres and partially covered by gold nanocrescents, produce efficient second harmonic generation signals due to the cooperative effect of localized plasmon excitation and 2D Bragg gratings. Asymmetries in the geometric shape of the gold nanocrescents induce a circularly polarized optical re...

We report on the strong coupling between the Bloch surface wave supported by an inorganic multilayer structure and $J$-aggregate excitons in an organic semiconductor. The dispersion curves of the resulting polariton modes are investigated by means of angle-resolved attenuated total reflection as well as photoluminescence experiments. The measured R...

We demonstrate control of the photoluminescence spectra and decay rates of water-soluble green-emitting conjugated polyrotaxanes by incorporating them in polystyrene opals with a stop-band spectrally tuned on the rotaxane emission (405-650 nm). We observe a suppression of the luminescence within the photonic stop-band and a corresponding enhancemen...

The synthesis and characterization of submicrometer-sized polymer particles, functionalized by different techniques with fluorescent dyes and featuring tunable surface charges, are described. Dyes with a polymerizable moiety were incorporated during emulsifier-free or seeded emulsion polymerization, whereas non-polymerizable dyes were included into...

Here we present the measurements of the second harmonic generation (SHG) signal raised by self ordered dielectric nanospheres partially covered by thin (10nm) Au layer. The measurement were performed by studying the SHG efficiency in different polarization states of the light. In particular measurement performed with circular polarized light show t...

The interaction of localized surface plasmon resonances (LSPRs) with the photonic modes in an opal photonic crystal is reported. Gold nanocrescents are evaporated at glancing angles over both microsphere monolayers and artificial opals. Microsphere monolayers allow the three localised plasmonic resonances observed in the nanocrescent optical spectr...

A seeded surfactant-free methyl methacrylate emulsion polymerization is employed to prepare coreshell particles with predetermined size and narrow size distribution. The particle size is determined by the ratio between methyl methacrylate (MMA, shell) and polytetrafluoroethylene (PTFE, core). Monodisperse particles in the 100350 nm range are obtain...