|M.Sc Student||Homede Abo Jabal Ekhlas|
|Subject||Printing Ultrasensitive Cross-Reactive Functional Sensors|
Array with a Single Droplet Containing
|Department||Department of Nanoscience and Nanotechnology||Supervisor||PROF. Hossam Haick|
|Full Thesis text|
Arrays of broadly cross-reactive sensors for the detection of wide range of chemical and biological compounds in different branches have a fundamental role in sensor technology. However, the need to achieve massive production rate along with large patterning areas with thin films at relatively low cost has driven extensive efforts to adapt ink-printing methods. Printed electronics is one of the main fields that captivates the worldwide market because of its potential in overcoming most of the challenges wrapped up in traditional fabrication ways of electrical devices.
We here present a new printing method to deposit a fully functional array of sensors based on monolayer-capped gold nanoparticles (Au-MCNPs). It is based on the finding of the self-propelled anti-pinning ink droplet, evaporative deposition from which takes place along its actuation path. These sensors array are potentially inexpensive, do not need complicated and expensive printing equipment and pre-patterning processes, could allow low voltage operation, and provide a platform for multifunctional applications. Using this approach, we show that a distinctive and controllable deposition patterns can be produced. For these deposited patterns, a film thickness gradient along the actuation path of the droplet could be achieved. Modifying the Au-MCNPs nano-structural parameters (ligand length) enables their electrical and sensing properties to be controlled and tuned. The chemiresistors arrays were exposed to different concentrations of representative polar and non-polar volatile organic compounds (VOCs) under an extreme range of humidities (0-90% RH). In general, we show that there is different sensing behavior for different printed patterns. Ultimately, we succeeded in producing ultra-sensitive fully functional cross-reactive a chemiresistor array with single droplet that has the ability to detect VOCs at low ppb levels.