2d Material Inks for Printed Electronics

Functional printing is a tried and tested method of low-cost and high-throughput production. Combining 2d materials with printing is an emerging, cost-effective and large-scale fabrication strategy of their devices. However, successful scale-up and adoption of printing as an ubiquitous fabrication method has been limited due to the lack of diversity in the available printing methods and materials. Since 2012, the majority of the 2d material printing demonstrations have been with inkjet. Methods such as blade coating, screen printing and flexography have received less attention despite having notable advantages. Also, the majority of 2d material printing research has focused on conducting (e.g. graphene) and semiconducting (e.g. black phosphorus) 2d materials and less emphasis has been placed on dielectric layers using wide bandgap 2d materials like hexagonal boron nitride (h-BN), which represent an important material in printed electronics applications, for example, in parallel plate capacitors and thin film transistors. Similarly, 2d material printing has thus far been demonstrated on flat surfaces, and little work has been done to print on conformal 3d objects. Conformal printing is an attractive and emerging field, which can enable the deposition of specific electronic features, such as sensors and circuits, directly on to 3d objects. Functional ink deposition on 3d structures is not a trivial process due to uneven and sometimes, complex topography. My PhD dissertation focuses on these key aspects of 2d material inks, I first present the formulation of conductive 2d material inks for screen printing. I begin to tackle the issues outlined above by using the screen inks to fabricate simple devices. I then combine screen printing with a water-based technique utilising a sacrificial layer that is capable of printing on to 3D objects. Next, I demonstrate and evaluate the feasibility of using flexographic printing as a means of large-scale fabrication via the high-speed printing of graphene-modified flexographic ink on a commercial press. Lastly, I investigate the use of h-BN as a dielectric nanofiller to enhance the dielectric properties of an existing dielectric polymer, polyurethane (PU). The work I present on conformal printing and in the formulation of dielectric inks in my thesis is my novel contribution to the research field. My research, therefore, addresses existing shortcomings of 2d material inks towards their large-scale exploitation.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2019

Author dc:creator

• Ng, Leonard

Advisor dc:contributor.advisor

• Hasan, Tawfique

• 2d materials
• graphene
• printing
• large-scale fabrication
• h-BN
• Dielectrics
• Conductive ink
• Conformal printing

Licence

• https://www.repository.cam.ac.uk/bitstreams/04ed6733-58d3-49ae-a1db-ac60f3b4693f/download
• https://www.rioxx.net/licenses/all-rights-reserved/

Language dc:language

en

Author Identifier

0000-0001-6062-7823
0000-0002-6250-7582

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/293528