2024 Investiture Information

All Thayer Events

PhD Thesis Defense: Congran Jin



1:45pm - 4:00pm ET


For info on how to attend this videoconference, email congran.jin.th@dartmouth.edu.

Zinc Oxide-Based Nanomaterials and Device Designs—for bioenergy harvesting, sensing and water purification


Harvested biomechanical energy from the human body can be used to power implantable electronics, such as cardiac pacemakers. This power strategy replaces conventional batteries and increases the lifespan of these electronics by offering a life-long energy solution. The electrical signals converted from the biomechanical motions contain vital physiological information such as heart rate and blood pressure. Therefore, it can also serve as a sensor that monitors one's health condition. This thesis proposes to exploit and enhance these inherent properties of ZnO by rationally designing its nano- and micron-structures and employing them, with other functional materials, in the development of novel biomechanical energy harvesting, water purification and sensing devices.

In this thesis, flexible energy harvesters and sensors, including implantable pacemaker-based EHs and wearable body motion sensors, are developed by incorporating rationally designed ZnO nano- and micron-materials by utilizing its piezoelectric property. The flexible energy harvester is biocompatible with its Young's modulus as low as 3.3 MPa, similar to that of skin, and can be stretched to 2.5 times its original length. The generated voltage reaches up to 9.2 V, and the power output generated from the animal test reaches 10.7 µW, sufficient to charge implantable electronics such as pacemakers.

In addition, this thesis proposes to develop a flexible nano-platform for water purification and contamination sensing. The device is fabricated by ZnO nanorods-coated silica nanofiber (SNF@ZnO NR) which is then decorated with Ag nanoparticles for enhanced surface plasmon. The preliminary result shows that degradation efficiency of organic contaminant is 98% under UV light, and the limit of detection is 1 ng/mL for the detection of organic dyes. The nanomaterial and device design strategies proposed in this study pave a new way for creating next-generation bioenergy harvesters, sensors and purification systems with outstanding performance.

Thesis Committee

  • John X.J. Zhang (Chair)
  • Laura Ray
  • Fiona Li
  • Marc Feldman (external member)


For more information, contact Theresa Fuller at theresa.d.fuller@dartmouth.edu.