Institute of Materials Research and Engineering (IMRE), A*STAR
Designing high performance thermoelectrics (figure of merit zT) involves navigating the complex interplay between electronic and thermal transports. Our group focuses on tailoring not only the microstructural properties of materials, but also their electronic and phonon band structures. This is done via intuitive understanding of solid state physics and chemistry, as well as the complex interplay of parameters making up zT.
Next-generation Energy Materials
via additive manufacturing
Our group focuses on all aspects of thermoelectrics, with specific focus on bulk inorganic materials. Tapping on the recent advancements in thermoelectric materials performance, we aim to explore the following areas:
- On-chip cooling for the electronics industry.
- Energy harvesting for aerospace industry (commercial airplane).
- Power for battery-less small unit wearable electronics, IoT devices, and implants.
- High Performance Thermoelectrics (inorganic bulk)
- Semiconductor Upcycling
- 3D-printed Thermoelectrics
- Flexible Bulk Thermoelectrics
- Thermoelectric Devices
High Performance Thermoelectrics (inorganic bulk)
End-of-life semiconductor electronics and metals can be re-engineered towards high-performance thermoelectrics. This can be done considering thermoelectrics are majority carrier device, making them generally defect-tolerant. Case in point the waste silicon from solar cells are generally not economical enough to be recycled, as it involves costly purification processes. By careful doping and alloying, the waste silicon can be re-purposed into silicon-based thermoelectrics for high temperature power generation, with potential applications in aircrafts and nuclear reactor.
More to follow...
Imparting flexibility into thermoelectrics is important to enable their applications in wearable devices. However, the state-of-the-art flexible devices based on organic materials are severely lacking in performance. This calls for solutions that can augment flexibility into stiff inorganic thermoelectrics. Our recent works utilizes self-healable and reprocessable polymers as the matrix to encapsulate thermoelectric devices. This makes it not only flexible, but also easily recyclable and reprocessable. More to follow...
Additive manufacturing has progressed rapidly in recent years, thanks to its versatility in printing complex and intricate shapes. Very recently, it has also been making inroads into functional and energy materials. On the other hand, thermoelectrics is a relatively mature field, with well-established understanding and design, especially on the materials level. However, complexities in device fabrication and scalability issues have greatly hindered thermoelectric applications.
The advent of additive manufacturing provides a timely and important tool not only to overcome the scalability issues, but also to achieve shape intricacies and conformability for flexible and wearable applications. In particular, direct ink writing, a subset under materials extrusion method, holds great promise as a versatile fabrication technique for integrated thermoelectric device. More importantly, we work towards “engineered nanostructuring” using direct ink writing as a new paradigm to improve thermoelectric performance beyond intrinsic properties. See our paper in ACS Energy Letters.
Flexible Bulk Thermoelectrics
Journal of Materials Chemistry A 9, no. 41 (2021): 23335-23344.
Our research group focuses on different aspects of electronic and thermal transport in energy materials. We aim to design the next-generation energy materials via additive manufacturing. Specifically, we go in-depth into thermoelectrics, with focus on energy harvesting and solid state refrigeration. Our work encompasses materials → processing/fabrication → applications.
Designing a high performance thermoelectric starts with high figure of merit, zT. In addition, good electrical and thermal contact quality is equally vital in ensuring low contact resistance and minimal parasitic losses. This includes ensuring compatibility between n-type and p-type thermoelectric legs, impedance matching, and also good thermal insulation between hot and cold end of the junctions.