Stimuli-Responsive Luminescent Materials: From Powders to Droplets

Prof. Che-Jen Lin is currently an Associate Professor in the Department of Chemistry at National Dong Hwa University. His research focuses on organic chemistry, soft materials, and luminescent materials, with particular emphasis on stimuli-responsive systems and functional emulsions. He earned his Ph.D. in Chemistry from National Taiwan University in 2017 under the mentorship of Prof. Jye-Shane Yang, and subsequently conducted postdoctoral research at the Massachusetts Institute of Technology (2017–2019) with Prof. Timothy M. Swager.

During his doctoral studies, Prof. Lin focused on luminescent stimuli-responsive materials, aiming to elucidate their structure–property relationships and to explore their potential in sensing applications.¹ Building on this foundation, he expanded his research during his postdoctoral work to include chemical sensing based on complex emulsions² and single-walled carbon nanotubes.³ His recent studies integrate complex emulsions with microfluidic technologies to enable real-time chemical sensing.⁴ He is also the inventor of a patented microfluidic detection chip and is currently developing a light-responsive colloidal system designed to create smart materials, with promising applications in microreactors and drug delivery.

Prof. Lin has received the Excellent Young Scholars Award from the National Science and Technology Council. Beginning August 1, 2025, he will join the Department of Chemistry at National Tsing Hua University, where he will continue advancing research in soft materials for sensing, sustainability, and photonic applications.

Stimuli-responsive luminescent materials, which alter their emission color in response to external triggers such as heat, vapor, or mechanical stress, are increasingly capturing interest in chemistry and materials science. A key factor in the design of these materials is the management of their intermolecular interactions, including van der Waals forces, hydrogen bonding, and metal-metal contacts. In this presentation, I will emphasize our recent discovery that fluorous interactions play a critical role in enabling color changes in pyrene-based materials when exposed to THF vapor and during mechanical grinding.¹

Expanding upon solid-state systems, we have investigated a dynamic platform based on complex emulsions made from immiscible hydrocarbon and fluorocarbon oils. By employing amphiphilic chromophores in place of traditional surfactants, we have successfully created self-stabilizing emulsions with tunable luminescence. Our materials include green fluorescent protein chromophores (GFPc)² and aggregation induced emission (AIE) systems,³ which demonstrate morphology-dependent emission. This discovery opens up new possibilities for responsive sensing applications.

To translate this concept into real-time detection, we developed a flow-injection analysis method using multi-well flow cells (MWFCs) integrated with our complex emulsions. With this system, we have successfully detected analytes such as iodine and per- and polyfluoroalkyl substances (PFAS) in aqueous environments by monitoring real-time changes in morphology and luminescence. This approach offers a costeffective and versatile alternative to traditional sensing instrumentation, presenting significant potential applications in environmental and chemical sensing.

1. C. Shirisha, P.-Z. Lai, J. Yang, C.-Y. Xu, C.-J. Lin; manuscript in preparation