Research

Research Vision

Fundamental Discoveries and Materials Innovation for Energy, Sustainability and Health

Inventing Atomic Multi-Modal Synthesis and Characterization Methods

Our research is supported by:

Basic Science

Industrial

Atomic-Scale Sustainable Materials and Manufacturing for CCUS

Climate, water, energy, and food are essential for human well-being, poverty reduction, and sustainable development. Global climate change creates critical challenges by increasing temperatures, reducing snowpack, and changing precipitation patterns for water, energy, and food, as well as ecosystem processes at regional scales. Ecosystem services provide life support, goods, and natural resources from water, energy, and food, as well as the environment. However, there are knowledge gaps resulting from a lack of conceptual frameworks and practices to interlink major climate change drivers of water resources with the climate-water-energy-food nexus and related ecosystem processes.

I have created solid adsorbent polymer materials that capture carbon dioxide from the air or exhaust streams of industrial processes. I developed and integrated diverse cutting-edge atomic-level toolboxes, including multidimensional and multinuclear quantitative solid-state NMR spectroscopy (1D SS-NMR (13CP/MAS, 1H) and 2D SS-NMR (2D Heteronuclear Correlation Spectroscopy-HETCOR, 2D 1H NMR Spin Diffusion)), atomic engineering, Cryo-EM, S/TEM atomic resolution imaging, electron energy loss spectroscopy (EELS), X-ray spectroscopy/microscopy, and synchrotron-XAS/computed micro-tomography/SAXS techniques, density-functional theory (DFT), molecular dynamics simulation, and gas adsorption methods. These tools were used to investigate how polymers adsorb target gas molecules (CO2) with high affinity and selectivity, as well as to reveal the unique interatomic interactions between CO2 and sustainable materials.

Bioinspired Single-Atom Catalysts

(Cui “galaxy” of single atoms was featured and chosen as a Happy Holidays highlight on the Molecular Foundry website at Lawrence Berkeley National Laboratory)

Single-atom catalysts (SACs) offer controllable coordination environments and exceptional atom utilization efficiency, revolutionizing the design of high-performance, sustainable catalysts. Aided by recent advances in practical synthetic methodologies, characterization techniques, and computational modelling, I have built single-atom catalysts (SACs) that exhibit distinctive performances for a wide variety of chemical reactions. I have also invented several synthetic methodologies and developed advanced atomic-resolution characterization techniques, such as S/TEM atomic resolution imaging, electron energy loss spectroscopy (EELS), X-ray spectroscopy/microscopy, and synchrotron-XAS/Micro-CT/SAXS techniques, as well as using density-functional theory (DFT) for atomically precise materials. Atomically dispersed metals that I invented have been applied to electrochemical interfaces and mental health management.

Natural Wood Cellulose Synthesis and Manufacturing

Atomic-Level Insights into Battery Systems:
From Nuclear Magnetic Resonance (NMR) to Electron Paramagnetic Resonance (EPR)

Solid-state nuclear magnetic resonance (NMR) spectroscopy is an atomic-level method to determine the chemical structure, 3D structure and dynamics of solids and semi-solids. NMR is particularly useful for studying the local environments of nuclei in materials, including lithium ions in battery electrodes. EPR, on the other hand, is used to study the spin properties of unpaired electrons in materials, providing information on the electronic structure and redox reactions that occur in battery systems. These advanced spectroscopic techniques provide valuable information on the atomic-scale structure and dynamics of battery materials. By combining these techniques with other advanced characterization methods, I can gain a deeper understanding of the fundamental processes that govern battery performance and develop more efficient and sustainable energy storage solutions.
I incorporate advanced characterization methods to obtain atomic-level insights into the mechanisms of operation and degradation in battery systems. I synthesize and manufacture new materials, perform electrochemistry, and employ state-of-the-art multimodal atomic-level tools, including solid-state nuclear magnetic resonance (SS-NMR) spectroscopy, pulsed-field gradient nuclear magnetic resonance measurements (PFG NMR), electrophoretic NMR (eNMR), magnetic resonance imaging (MRI), dynamic nuclear polarization (DNP) spectroscopy, X-ray diffraction, and X-ray spectroscopy/imaging techniques (XAS, XANES, EXAFS, computed micro-tomography, XRF), as well as high-resolution X-ray and neutron diffraction. Our unique solid-state NMR instrumentation spans 700 MHz, 500 MHz, and 400 MHz superconducting magnets with Bruker spectrometers and an array of new probes from Phoenix NMR. To complement our experimental work, we also conduct electronic structure calculations and numerical simulations, working closely with simulation collaborators and national labs.
In addition to state-of-the-art NMR and EPR, I have access to a range of other techniques, such as X-ray synchrotron studies, neutron diffraction, infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron (XPS) spectroscopy, advanced cryogenic electron microscopy (Cryo-EM), cryogenic Focused Ion Beam SEM (Cryo-FIB-SEM), gas chromatography, and mass spectrometry. These complementary methodologies offer unique information on battery systems and help to further deepen our understanding of these complex systems.

The Bionic Eye with an Artificial Retina : Bioelectronics-enabled Restoring Vision

"The NanowireRetina—a new generation of implantable artificial retina to restore vision" - by MIT Technology Review
This breakthrough pioneered the development of nanowire arrays for retinal implants.

A brain–machine interface (BMI) is a device that translates neuronal information into commands capable of controlling external software or hardware such as a computer or robotic arm. BMIs are often used as assisted living devices for individuals with motor or sensory impairments.
Retinal prostheses for restoration of sight to patients blinded by retinal degeneration are being developed by a number of private companies and research institutions worldwide. The system is meant to partially restore useful vision to people who have lost their photoreceptors due to retinal diseases such as retinitis pigmentosa (RP) or age-related macular degeneration (AMD). Three types of retinal implants are currently in clinical trials: epiretinal (on the retina), subretinal (behind the retina), and suprachoroidal (between the choroid and the sclera). Retinal implants introduce visual information into the retina by electrically stimulating the surviving retinal neurons. So far, elicited percepts had rather low resolution, and may be suitable for light perception and recognition of simple objects.
I developed the NanowireRetina—a new generation of implantable artificial retina to restore vision. This breakthrough also pioneered the development of nanowire arrays for retinal implants. The restoration of light response with complex spatiotemporal features in retinal degenerative diseases towards retinal prosthesis has proven to be a considerable challenge over the past decades. Herein, inspired by the structure and function of photoreceptors in retinas, I develop artificial photoreceptors based on gold nanoparticle-decorated titania nanowire arrays, for restoration of visual responses in the blind mice with degenerated photoreceptors. Green, blue and near UV light responses in the retinal ganglion cells (RGCs) are restored with a spatial resolution better than 100 µm. ON responses in RGCs are blocked by glutamatergic antagonists, suggesting functional preservation of the remaining retinal circuits. Moreover, neurons in the primary visual cortex respond to light after subretinal implant of nanowire arrays. Improvement in pupillary light reflex suggests the behavioral recovery of light sensitivity. My study will shed light on the development of a new generation of optoelectronic toolkits for subretinal prosthetic devices. Through pharmacological, optical, ultrasound and electrical toolsets, I aim to develop effective therapeutic solutions to neurological disease states.

Shining Light on the Nervous System: from Biomaterials to Bioelectronics

Pain Management

Gene/Drug Delivery

Neurological disorder is a complex medical problem that can have profound effects on your physical and mental well-being. My goal is to help you decrease your level of pain and suffering, to return you to your maximum level of functioning and independence, and to help you restore your quality of life.
I developed a light triggered smart drug release device system. Current treatments of pain heavily rely on opioids, resulting in significant side effects such as addiction, tolerance, leading to the Opioid Overdose Crisis as we know of today. Smart drug delivery systems may provide an effective solution. Here I present the development of externally-triggerable drug delivery systems for on-demand, repeatable and adjustable local anesthesia using new polymer nanoparticles, where the timing, duration, and intensity of nerve block can be controlled through external energy triggers such as the optical tool. In addition to traditional pharmacological approaches, bioelectronic platforms to enhance our insights into the retina.

Biosensors for Health Monitoring and Early Diagnosis

Precision Health reimagines medicine to focus on predicting, preventing, and curing disease precisely. Marrying two seemingly different approaches-high-tech and high-touch-this vision tailors health care to the unique biology and life circumstances of each individual, with an emphasis on catching disease before it strikes. Precision Health represents a fundamental shift to more proactive and personalized care that empowers people to lead healthy lives.
The field of photoelectrochemical (PEC) bioanalysis has made significant progress in recent years, resulting in improved analytical performance and biodetection applications. PEC sensors offer a unique way to detect chemical and biological substances, with a focus on optimizing semiconductor composition and electronic structures, surface functionalization layers, and chemical detection methods. In this context, I would like to highlight my recent research on nanowire-based PEC sensing, which incorporates three main detection mechanisms and corresponding examples. Additionally, my work involves real-time molecular reaction kinetic measurements, as well as direct interfacing with living cells and probing of cellular functions. These findings offer valuable insights for researchers interested in the latest developments and applications of PEC bioanalysis, and can serve as a useful resource in the field.