Aquivion–Poly(<i>N</i>‐vinylcarbazole) Holistic Flory–Huggins Photonic Vapor Sensors (Advanced Optical Materials 5/2021)

Megahd, Heba; Oldani, Claudio; Radice, Stefano; Lanfranchi, Andrea; Patrini, M.; Lova, Paola; Comoretto, Davide

doi:10.1002/adom.202170017

Cited by 4 publications

(6 citation statements)

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“…The optical response of the structure was simulated using the complex refractive index dispersions of all the polymers employed that were previously reported in the literature, 2,3,24,32 and that measured for the DPP:PS film (Supporting Figure S4). Employing transfer matrix method (TMM) modeling, 3 the simulated transmittance reported in Figure 2a (dotted line) was best-fit to the experimental one, yielding the thicknesses of individual materials (74.5 nm for PVK, 159.5 nm for AQ, 184 for DPP:PS, and 78 nm for the CA layers).The positions and widths of the interference fringes, as well as the PBG and λ c in the experimental measurements, are all well-reproduced in the calculation.…”

Section: ■ Resultsmentioning

confidence: 99%

“…However, this is expected as AQ, being a material sensitive to its chemical environment, is strongly perturbated by the abrupt change induced by the freeze-cracking process and the subsequent vacuum environment of the SEM chamber. 2 Figure 2d compares the PL spectra for a DPP:PS thin film and MC tuned . Both the DPP:PS layer in the microcavity and that in the reference DPP:PS film were cast under identical conditions.…”

Section: ■ Resultsmentioning

confidence: 99%

“…In this work, we unambiguously demonstrate radiative rate suppression within a planar polymer MC fabricated through the solution processing of a perfluorinated polymer, Aquivion (AQ, n = 1.35), 2 and polyvinylcarbazole (PVK, n = 1.69). 3,24 The couple provides the highest dielectric contrast demonstrated for polymer planar microcavities (Δn = 0.34 in the UV-NIR range) so far.…”

Section: ■ Introductionmentioning

confidence: 99%

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All-Polymer Microcavities for the Fluorescence Radiative Rate Modification of a Diketopyrrolopyrrole Derivative

et al. 2022

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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 Purcell effect with polymer structures are controversial, as the low dielectric contrast typical of suitable polymers is commonly not enough to provide the necessary confinement. Here we show all-polymer planar microcavities with photonic band gaps tuned to the photoluminescence of a diketopyrrolopyrrole derivative, which allows a change in the fluorescence lifetime. Radiative and nonradiative rates were disentangled systematically by measuring the external quantum efficiencies and comparing the planar microcavities with a series of references designed to exclude any extrinsic effects. For the first time, this analysis shows unambiguously the dye radiative emission rate variations obtained with macromolecular dielectric mirrors. When different waveguides, chemical environments, and effective refractive index effects in the structure were accounted for, the change in the radiative lifetime was assigned to the Purcell effect. This was possible through the exploitation of photonic structures made of polyvinylcarbazole as a high-index material and the perfluorinated Aquivion as a low-index one, which produced the largest dielectric contrast ever obtained in planar polymer cavities. This characteristic induces the high confinement of the radiation electric field within the cavity layer, causing a record intensity enhancement and steering the radiative rate. Current limits and requirements to achieve the full control of radiative rates with polymer planar microcavities are also addressed.

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Section: ■ Resultsmentioning

confidence: 99%

Section: ■ Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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All-Polymer Microcavities for the Fluorescence Radiative Rate Modification of a Diketopyrrolopyrrole Derivative

et al. 2022

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“…We have indeed previously shown that engineered multilayered polymer structures significantly influence the diffusion behavior in photonic sensors based on the Flory-Huggins solution theory. [23] The specific polymer-solvent interactions, represented by the Flory-Huggins interaction parameter 𝜒, of a polymer-solvent pair are also expected to influence the quenching kinetics. As the value of 𝜒 increases, the permeability of the solvent in the polymer strongly decreases, [24] causing a barrier effect.…”

Section: Introductionmentioning

confidence: 99%

Controlled Molecular Diffusion in Fluorescent Polymer Films for Label‐Free Detection of Volatile Organic Compounds

Megahd,

Carlotti,

Martusciello

et al. 2023

Advanced Sensor Research

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Aggregation‐induced emission has eliminated the problem of fluorescence quenching in the solid state, making molecules with this property excellent candidates for vapor sensing due to their portability and ease of interpretation. Here, films of polystyrene / 2‐[4‐vinyl(1,10‐biphenyl)‐40‐yl]‐cyanovinyljulolidine copolymers are reported that exhibit aggregation‐induced emission behavior for the detection of toluene, m‐xylene, dichloromethane, and chloroform. After exposure to the analytes, the emission of the copolymers shows significant changes in intensity and spectral shape corresponding to the reduced microviscosity of the molecular environment. However, these changes are similar for different analytes, resulting in low chemical selectivity. Therefore, label‐free selectivity is achieved by controlling the molecular diffusion of the four vapor analytes within the films using the Flory–Huggins solution theory with capping layers of cellulose acetate (CA) and poly(vinyl alcohol) (PVA) polymers.

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“…26 Indeed, thanks to a relatively low dielectric contrast among polymers, they can be designed to have narrow PBGs. 26 Also, polymer multilayers can be grown using various simple and fast techniques, such as copolymer self-assembly, 34,35 dip coating, 36 spin coating, 37 and even coextrusion, 25 an industrial method that makes them compatible with current packaging production. 25,38 In this context, we propose a hybrid polymer−inorganic DBR for the detection of biogenic amines in the vapor phase.…”

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confidence: 99%

Beyond Labeling: Hybrid Planar Photonic Crystals for Anti-tampering Detection of Amines

Escher,

Alloisio,

Cavallo

et al. 2024

ACS Appl. Opt. Mater.

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Smart packaging promises to protect consumer health and safety, reduce food waste, and decrease energy and resource consumption. In other words, less food waste leads to better living conditions, decreasing plastic waste and greenhouse gas emissions. This work aims to create a colorimetric label for assessing food freshness by monitoring biogenic amines, which are the typical degradation byproducts of protein-based food such as meat, fish, and seafood. We focus on planar photonic crystals consisting of alternating thin films of a titanium dioxide-poly(acrylic acid) hybrid as a high-refractive-index medium and a blend of polystyrene and polylactic acid as a low-index and sensitive material. The colorimetric response of these sensors can be detected by visible reflectance spectroscopy and is visible to the naked eye, allowing a straightforward interpretation by any user. The response is tested for a prototype amine and for chicken meat, and it is caused by the loss of the structural color of the dielectric lattice resulting from the aminolysis of the polylactic acid that induces the collapsing of the rigid hybrid layers, thus providing effective nonreversible antitampering systems for smart labeling.

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Aquivion–Poly(N‐vinylcarbazole) Holistic Flory–Huggins Photonic Vapor Sensors (Advanced Optical Materials 5/2021)

Cited by 4 publications

References 0 publications

All-Polymer Microcavities for the Fluorescence Radiative Rate Modification of a Diketopyrrolopyrrole Derivative

All-Polymer Microcavities for the Fluorescence Radiative Rate Modification of a Diketopyrrolopyrrole Derivative

Controlled Molecular Diffusion in Fluorescent Polymer Films for Label‐Free Detection of Volatile Organic Compounds

Beyond Labeling: Hybrid Planar Photonic Crystals for Anti-tampering Detection of Amines

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