Nanoparticle Sensor Arrays on Flexible Substrates (EN)

Ασλανίδης, Ευάγγελος

Προδρομάκης, Θέμης

Ζεργιώτη, Ιωάννα

Χριστοφόρου, Ευάγγελος

Παπαβασσιλείου, Χρήστος

Τσουκαλάς, Δημήτρης

Ράπτης, Ιωάννης

Κυρίτσης, Απόστολος

ntua (EL)

Φυσικής (EL)

The main subject of the current thesis is the development and study of operation of metallic nanoparticle-based flexible strain sensors. In addition, it is presented how Al2O3 (alumina) thin films were developed by Atomic Layer Deposition (ALD) for sensors protection against humidity. A study concerning the strain sensor’s characteristics before and after the deposition of alumina was carried out. Additionally, the already existing theory that describes the behavior of nanoparticles-based strain sensors was enriched in order to include the sputtering made nanoparticles. Throughout our study was successfully determined the critical thickness of the alumina film for the isolation and sufficient protection of nanoparticles from humidity. Apart from that, a Monte Carlo simulation tool that was written in Matlab, is developed to predict the sensitivities of various nanoparticle film under strain. This tool is capable of predicting the strain-sensitivity for different nanoparticle diameters as well as surface coverages, emerging as a powerful computational tool for design and optimization of nanoparticle based devices, while it could be extended to other nanocomposite materials used in flexible or stretchable electronic applications. Moreover, highly sensitive flexible strain sensors formed by a network of metallic nanoparticles on top of a cracked thin alumina film were fabricated and discussed. Sensors’ sensitivity depends on the nanoparticles’ surface density as well as on the thickness of alumina thin films. Both can be well controlled via the deposition techniques. A record strain sensitivity value of 2.6 × 108 was achieved by the sensors at 7.2% strain, while exhibiting high sensitivity in a large strain range from 0.1% to 7.2%. The demonstration is followed by a discussion enlightening the physical understanding of sensor operation, which enables the tuning of its performance according to the above process parameters. Finally, a strain sensor array was develop on a glove and measured by a custom made circuit. The measurements of the circuit were compared with measurements from a Keithley 2400 and found to be very precise in the operational range of the circuit. (EL)

doctoralThesis

strain (EL)

sensors (EL)

Νανοσωματίδια (EL)

αισθητήρες (EL)

προσομοίωση (EL)

simulation (EL)

nanotechnology (EL)

παραμόρφωση (EL)

Νανοτεχνολογία (EL)

nanoparticles (EN)

Εθνικό Μετσόβιο Πολυτεχνείο

Ψηφιακό Αποθετήριο της Κεντρικής Βιβλιοθήκης του ΕΜΠ | Dspace@NTUA

Κεντρική Βιβλιοθήκη Ε.Μ.Π.

Ιδρυματικό Αποθετήριο

Διδακτορικές Διατριβές

Αγγλική γλώσσα

2021-04-22

http://dx.doi.org/10.26240/heal.ntua.21923

https://dspace.lib.ntua.gr/xmlui/handle/123456789/54225