Light-Activated Porphyrinoid-Capped Nanoparticles for Gas Sensing

Abstract

The coupling of semiconductors with organic molecules results in a class of sensors whose chemoresistive properties are dictated by the nature of dyes. Organic molecules generally reduce conductivity, but in the case of optically active dyes, such as porphyrinoids, the conductivity is restored by the illumination with visible light. In this paper, we investigated the gas sensing properties of ZnO nanoparticles coated with porphyrins and corroles. Under light illumination, the resistance of these materials increases with the adsorption of volatile compounds but decreases when these are strong electron donors.The behavior of these sensors can be explicated on the basis of the structural difference between free-base porphyrin and corrole, the influence of coordinated metal and the corresponding electronic structures. 2These sensors are promising electronic noses that combines the selectivity to strong electron donors with the broad-selectivity towards the other classes of chemicals. An efficient representation of the data of this peculiar array can be obtained by replacing the Euclidean distance with the angular distance. To this end, a recently introduced spherical principal component analysis algorithm is applied for the first time to gas sensor array data. Results show that a minimal gas sensor array (four elements) can produce a sort of chemotopic map which enables to cluster a very large class of pure chemical vapors. Furthermore, this map provides information about the composition of complex odor matrices, such as the headspaces of beef meat and their evolution over the time.

Corroles at work: a small macrocycle for great applications

“…186 A further example of the electronic nose was given by an array of four resistive porphyrins and corroles-functionalized ZnO nanoparticles assembled and tested as compared to various volatile compounds and real samples too. 158 The results show that the array, although limited in terms of the number of sensors, was sensitive and selective enough to identify the various compounds. The arrangement of the volatile compounds in the PCA score plots is similar to the projection of olfactory neurons into the olfactory bulb where similar compounds were mapped in closed regions.…”

“…157 The similarities between corroles and porphyrins suggested the development of light-activated gas sensors made of corrolecoated ZnO nanoparticles. 158 A one-pot fabrication procedure was prepared where corrole was added to the precursor of the ZnO hydrothermal synthesis precursor (see Fig. 69).…”

“…The behaviors of corrole-based sensors were compared with those of porphyrin-based sensors. 158 In particular, the sensitivities of free-base macrocycles and copper complexes of TPPH 2 and TPCorrH 3 were compared. Compared to porphyrins, the corrole cavity is characterized by an additional hydrogen atom that leads to a non-planar structure and a larger acidity, increasing hydrogen bond affinity, which favors the ligand as compared to alcohols and bases.…”

Paving the Way for a Green Transition in the Design of Sensors and Biosensors for the Detection of Volatile Organic Compounds (VOCs)

“…The review highlights recent trends in the research of green approaches to substitute and replace classic poorly sustainable sensors, in line and accordance with the most recent environmental policies and researchers’ ethical spirt of sustainable growth. These approaches include manufacturing processes carried out using biomass and waste derived materials, the use of abundant elements in place of rare metals, the design of low energy consuming methods or the exploitation of biological activities, exploiting innovative technologies such as printed electronics, nanotechnology, silicon photonics, or biotechnology [ 88 , 89 , 90 ].…”

Highly sensitive and low-power consumption metalloporphyrin-based junctions for COx detection with excellent recovery

“…See DOI: https://doi.org/10.1039/d2cp00408a ideal playground for discovering practical sensors, and why not when nature uses FePor to sense and transfer oxygen molecules. 18 As such, MPor-based materials have been investigated to detect volatile organic compounds, [19][20][21] and metal ions. 22 Confirmed by previous experimental and theoretical studies, electrical conductivity in MPor-based molecular objects changes upon adsorption of polar gases such as CO and NO.…”