Persistent luminescence (PersL) is a unique optical property where a material exhibits long-lasting luminescence after the stoppage of the excitation source. The "glow-in-the-dark" property of PersL materials can be applied in various fields, including lighting, displays, and sensing. 

Nanoparticles with PersL at wavelengths in the near-infrared (NIR) is particularly beneficial for improving the signal quality in optical imaging and imaging-guided theranostics. A potential application currently being explored is drug delivery. Research under this theme focuses on investigating the luminescence mechanism and designing new materials with longer luminescence lifetimes. 

In the rapidly evolving field of phosphor-converted light-emitting diodes (pc-LEDs), our research focuses on the design and synthesis of novel phosphor materials that enable enhanced energy conversion efficiency, exceptional long-term stability, and precise color tunability. By engineering phosphors with optimized host lattices, dopants, and particle morphologies, we aim to minimize thermal quenching and luminous degradation, thereby extending device lifespan and maintaining high luminous efficacy. 

X-ray absorption fine structure (XAFS) spectroscopy is a powerful technique for probing oxidation states and local coordination geometry. Once used to be a “synchrotron-facility-only” type of characterization, lab-based XAFS has been developed which offers greater flexibility and faster iteration in research workflows. Since the technique was new and there were only a few working models on the market, applying lab-based XAFS into routine research still requires further evaluation, such as exploring its full capability and addressing its limits. The Liu group uses lab-based XAFS to examine advanced phosphor materials and beyond (including materials in batteries, catalysis, and geological mineral systems), to gain deeper understanding on the materials structure-property relationship.