STM 15

Three-dimensional graphene on a nano-porous 4H-SiC backbone: a novel material for food sensing applications

We have recently developed a high quality graphene in a three-dimensional arrangement (3DG) grown on porousified 4H-SiC(0001). This novel material represents an ideal platform for sensing applications. Indeed, nanoporous materials are a versatile solution for many applications, in particular for sensing. The 3DG material has a high surface-to-volume ratio. Here, the surface area of 3DG is more than two orders of magnitude greater than the top surface area alone. The synergy between the outstanding properties of graphene with a three-dimensional porous structure, circumventing the limits of the 2D nature of graphene, constitutes therefore a breakthrough for many fields.

Sensors which are sensitive to volatile organic compounds (VOCs) and thus able to monitor the conservation state of food, are precious because they work non–destructively and allow to avoid direct contact of the food with the sensor, ensuring hygienic conditions. The sensor that we have developed is produced utilizing a 3DG sample (see Fig. 1a) without further functionalization. The structure of the sensor surface features a large amount of edges, dangling bounds, and active sites, which make the sensor, on a chemically robust skeleton, chemically active, particularly to hydrogenated molecules.


Figure 1: (a) Scanning electron microscopy image taken at 5 kV (beam current 11.7 pA) on the cross-sectional edge of a 3DG sensor mechanically cleaved. The scale bar corresponds to 300 nm. b) Variation in sensor temperature and resistance for 15 minutes, including the switching on of the temperature stabilization. The reddish area visualizes the effect of a ±0.5◦ C temperature fluctuation on the resistance readout.

The sensor signal is represented by the variation of the resistance of the 3DG measured in a four–wire (4W) configuration. An alternating current of I = 1 µA is supplied to the sensor while the voltage drop V4W is measured with a lock-in amplifier (see Fig. 1b). This technique allows a sensitive measurement of the sensor resistance Rs with negligible impact from the contact resistance. The ability of the sensor to detect VOCs related to the degradation of the preservation state of hazelnuts has been demonstrated utilizing three hazelnut batches. The first was made by perfectly preserved hazelnuts, the second by spoiled hazelnuts, and the third by stink bug hazelnuts. A resistance variation of about ∆R = 0.13 ± 0.02 Ω between sound and damaged hazelnuts has been detected (see Fig. 2). Our measurements confirm the ability of the sensor to discriminate between sound and damaged hazelnuts. The sensor signal is stable for days, providing the possibility to use this sensor for the monitoring of the storage state of fats and foods in general.

Figure 2: Sensor resistance in a series of measurements during more than 20 days. The black points represent blanks (no nuts), blue points refer to the sensor exposed to sound hazelnuts, green points to stink bug hazelnuts, and red points to spoiled hazelnuts.

Publications:

  1. Stefano Veronesi, Ylea Vlamidis, Letizia Ferbel, Carmela Marinelli, Chiara Sanmartin, Isabella Taglieri, Georg Pfusterschmied, Markus Leitgeb, Ulrich Schmid, Fabio Mencarelli, Stefan Heun: Three-dimensional graphene on a nano-porous 4H-SiC backbone: a novel material for food sensing applications, arXiv:2309.13431 [physics.app-ph].
  2. Stefano Veronesi, Ylea Vlamidis, Letizia Ferbel, Carmela Marinelli, Chiara Sanmartin, Isabella Taglieri, Georg Pfusterschmied, Markus Leitgeb, Ulrich Schmid, Fabio Mencarelli, Stefan Heun: Three-dimensional graphene on a nano-porous 4H-SiC backbone: a novel material for food sensing applications, J. Sci. Food Agric. 2023, Accepted Author Manuscript.
  3. Epitaxial graphene growth on porous 4H-SiC(0001): a versatile platform for gas storage and sensing, CNR Nano Activity Report 2024. [Pages 84-85]

Presented at:

  1. Stefano Veronesi: 3D-graphene grown on nano-porous backbone, a novel material for food sensing applications, Workshop “OUTSTANDING SENSORS CHALLENGE BEVERAGE and FOOD FUTURE”, University of Pisa, Italy, May 5, 2023. [Talk]
  2. Stefano Veronesi: Epitaxial graphene on a 3D porous structure: toward hydrogen storage and sensing applications, National Graphene Institute, The University of Manchester, Manchester, UK (Prof. Radha Boya), 1 December 2023. [Talk]