New materials for flexible electronics

New materials for flexible electronics

Supervisor: Dr Emily Draper

School: Chemistry

Description: Flexible devices are crucial for wearable electronics that can be used to aid with movement of less abled bodied people. These devices need to be comfortable for the wearer and be able to respond to small stimulus such as movement or small electrical signals. This project focusses on preparing new types of materials for flexible electronics. We will align soft materials prepared from assembled small molecules for electronic materials in flexible thin film devices. Small organic molecules offer a great alternative to inorganic materials. They are less expensive, and have a great diversity in the functional groups that can be used making them more easily processed, thinner and more comfortable to wear. Small organic molecules are also interesting as the same molecule can form many different structures by altering the assembly conditions.

This project will involve using electronically active small molecules that self-assemble into different aggregated materials in water. Depending on the pH, solvent, salts and temperature used to prepare solutions leads to different structures being formed. These structures will then be dried down into thin films and tested for electronic activity. The best materials are can then be tested and used in devices as transistors and sensors flexible electronic materials. 

We have published widely showing that the aggregates formed in solution have a great influence on the final properties of the materials formed from the solution. We are able to align self-assembled aggregates on a rheometer using a shear force. We can align worm-like micelles formed from our electronically active small molecules giving directional dependence of current. Here, we plan to alter the length and/or thickness of the worm-like micelles formed in solution by changing the assembly condition of the solution. This will allow us to align the materials to different extents. This alignment allows materials to more efficient and conductive as the electrons will only be able to pass in one direction and prevents recombination of charges formed in the materials when used in a device. The student will specifically examine altering the conditions of the aggregated materials to understand which conditions give the most promising structures for alignment, which can be visualised using our new RheoOptics set-up. The aligned materials will then be tested for the highest electrical activity using a potentiostat. The best materials will then be used as the active layer in a thin film transistor which is the building block for most electronic devices.

Overview of training provided: The student will be trained on how to use specialist equipment such as a rheometer and a potentistat, and then trained how to put together and interpret data collected from these instruments. The student will learn how to prepare thin film devices from the solutions they have made. Training on the equipment and learning how to prepare solutions and thin films would occur in the first two weeks, and data collection and analysis would occur in the remaining weeks. They will have day to day support from Dr. Draper in Prof. Dave Adams’ lab, but if Dr. Draper was not available appropriate supervision from the Adams lab would be found. They will learn how to keep accurate notes in the lab as the project will involve changing a lot of conditions to see which ones give the best materials. The student will have weekly meetings with Dr. Draper in which they will learn how to present their data from that week as well the opportunity to discuss the results and the best direction for the work to go. They will also write a monthly report and receive feedback as to improve their scientific writing skills. The student will also present their findings to the Adams group in their group meetings in the form of a presentation. This gives the student a chance to practice many forms of data presentation which are invaluable in their future career. Dr. Draper has supervised a large number of Erasmus, MChem, BSc, MSc, Nuffield and summer bursary students and has an excellent track record of students publishing from their projects (Nanoscale, 2014, 6, 13719-13725; Soft Matter, 2017, 13, 1914-1919; CrystEngComm, 2015, 17, 8047-8057; Chem, 2017, 2, 1-16).