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Zhao Fu: Improving flexible & stretchable electronics by understanding their reliability limits and failure mechanisms

Tampereen yliopisto
SijaintiKorkeakoulunkatu 1, Tampere,
Hervannan kampus, Tietotalo, sali TB109 ja etäyhteys
Ajankohta28.6.2024 9.00–13.00
PääsymaksuMaksuton tapahtuma
Kuva: Saara Pitkälä-Fu
In his doctoral dissertation, MSc Zhao Fu studied the reliability of printed flexible & stretchable electronics using mechanical reliability testing and investigated their failure mechanisms through electrical characterization and imaging methods. He discovered that mechanical impacts caused mostly adhesive failures at the interfaces of two contacting components and cohesive failures within the component materials. His thesis provides guidelines for improving the reliability of printed flexible & stretchable electronics.

The widespread use of electronic devices in the industrial and societal sectors has greatly enhanced our work efficiency and the convenience of our life through digitalization. However, hard materials limit their application in situations where an electronic device needs to change its shape, for example, bend on the human arm.

Flexible & stretchable electronics overcome this limitation by incorporating mechanical deformability into the electronic materials, allowing them to be bent, compressed, and stretched while maintaining functionality. However, they still face challenges in long-term durability due to immature technologies, insufficient understanding of their failure mechanisms, and a lack of testing standards.

To address these challenges, MSc Zhao Fu aimed to understand the failure mechanisms of the flexible & stretchable electronics under repeated mechanical impacts such as bending, rolling, and rubbing, to identify the factors leading to their failures, and to provide knowledge on how to improve their reliability and performance.

In his dissertation, Fu and his colleagues developed automatic and cyclic mechanical testing methods and used them to evaluate the reliability of the flexible & stretchable electronics. He used imaging to analyze the locations and mechanisms of failures. Besides, he studied the impact of substrate fabrication processes on the interface adhesion.

Throughout his investigation, he revealed that the failures in flexible & stretchable electronics are related to the materials’ properties, device design, and fabrication process, which are also areas for potential improvement in reliability.

“By investigating the reliability limits and failure mechanisms of the flexible & stretchable electronics, we can understand their weaknesses, and use that knowledge to improve their performance. To ensure high reliability, it is crucial to understand how these devices fail when under impacts. This research helps us understand what’s the failures and weaknesses of the flexible & stretchable electronics and provide guidelines to improve them,” says Zhao Fu. 

Zhao Fu works at the Laboratory for Future Electronics at Tampere University. He is interested in the research that contribute to the reliability of flexible and stretchable electronics, sensors made from sustainable materials and efficient fabrication methods.

Public defence on Friday 28 June

The doctoral dissertation of M.Sc. Zhao Fu in the field of Electrical Engineering titled Mechanical Reliability and Failure Mechanisms of Printed Flexible & Stretchable Electronics will be publicly examined at the Faculty of Information Technology and Communication Sciences at Tampere University in room TB109 of the Tietotalo building (Korkeakoulunkatu 1, Tampere) at 12:00 on Friday 28 June 2024.

The Opponent will be Senior Associate Professor Klas Tybrandt, Head of Soft Electronics Group at Linköping University, Sweden. The Custos will be Professor Matti Mäntysalo, Tampere University.


The doctoral dissertation is available online

The public defence can be followed via remote connection