1. Fundamentals of energy conversion at dynamic materials interfaces
Energy conversion phenomenon can be found everywhere: from solar fusion and water flow, to photosynthesis and human metabolism. Modern technologies such as photovoltaics, electromagnetic generator, thermoelectric generator are able to convert various energy sources (irradiation, mechanical energy, heat, etc.) into electricity. In those technologies, advanced materials play an crucial role. Understanding and manipulating the fundamental physics at energetically excited materials surfaces and interfaces is the key to improve the performance of energy harvesting and storage devices, as well as to identify next-generation renewable energy solutions. We are interested in studying nanoscale multi-physics interactions such as electro-mechanical and photo-electro-mechanical coupling at dynamic material systems such as metal/semiconductor, semiconductor (P)/semiconductor (N), and two-dimensional (2D) materials and their heterojunctions.
Representative work:
2. Self-powering solution for wearable electronics and Internet of Thing (IoT) sensors
The growing demand for sustained power is one of the main challenges for sensors, wearable electronics, implantable devices, etc., which are the critical elements for future Internet of Things (IoT). With recent advances in sensors, new low power wireless networks and cloud processing, the Industrial Internet of Things (IIoT) has come of age. However, the problem of powering systems in the field at low cost, efficiently and for extended periods has remained unsolved. Meanwhile, the rising environmental concerns for the disposal of Li-ion batteries have been driving the legislation of regulations/laws in many countries. We are dedicated to developing self-powering solutions that can readily convert energy from environment/human activity into electricity, which are in collaboration with multiple industrial partners such us Sony, Corning, TSI etc.
Representative work:
2. R. Yang, et al. 'High‐Performance Flexible Schottky DC Generator via Metal/Conducting Polymer Sliding Contacts' Advanced Functional Materials, 2021
3. Physics, chemistry, and nanomechanics at solid-liquid interfaces
Solid-liquid interfaces play important roles in various applications such as electrochemical energy conversion and storage, petroleum industries, heterogeneous catalysis, corrosion, water management and treatment, etc. As a result of the symmetry breaking of solid and liquid, solid-liquid interfaces are inherited with rich sciences and many of which are yet to be understood. We are specifically interested in understanding chemical-electronic-mechanical relationship at the interfaces and exploring novel strategies in improving transport and energy efficiency in different applications with solid-interfaces involved. Scanning Probe Microscopy (SPM) is a powerful nanomechanical tool, not only able to visualize the appearance of the nano-world, but also capable of investigating fundamental physical, chemical, and bio-physical properties of both materials and microorganisms. Dr. Liu's lab is equipped with an environment-controlled, multi-functional SPM platform with many different modules (C-AFM, KPFM, EFM/MFM, SThM, PFM, Photoconductive AFM, Electrochemical-AFM, liquid-AFM) for advanced materials and biophysics studies.
Fig: Current Opinion in Colloid & Interface Science 39 (2019): 148-161.
Representative work:
2. J. Liu, et al. 'Mapping and quantifying surface charges on clay nanoparticles' Langmuir 2015