Title: "Metal Chalcogenide Quantum Dot Gels for Gas Sensing and Photocatalysis"

Long Luo, Associate Professor

University of Utah, Dept of Chemistry 

Host: Frederic A. Perras

Abstract: Metal chalcogenide quantum dot (QD) gels are macroscopic porous materials composed of interconnected QDs and three-dimensional pore networks, in which the pores are filled with either solvent (wet gels) or air (aerogels). These materials uniquely combine the processability of macroscopic solids with the size-dependent quantum-confined properties of their constituent QDs. Their high porosity further ensures that nearly every QD within the gel network is accessible to the surrounding environment, making QD gels attractive for applications that benefit from large surface areas, including gas sensing and (photo)catalysis.

Metal chalcogenide QD gels have traditionally been synthesized through chemical assembly routes. We expanded the synthetic toolbox by developing electrochemical gelation methods for QD assembly. Compared with conventional chemical oxidation approaches, electrochemical gelation introduces two additional parameters for controlling gel formation and structure—electrode material and applied potential—while also enabling direct gel growth on device substrates, thereby simplifying device fabrication and improving reproducibility. We further demonstrated that covalently assembled electrochemical QD gels can be post-synthetically modified through controlled ion exchange to produce single-ion-decorated bimetallic QD gels with precisely tailored compositions.

These electrochemically assembled QD gels exhibit unprecedented performance for NO₂ gas sensing and enable unique photocatalytic hydrogen atom transfer reactions. More broadly, the fundamental insights gained from electrochemical QD gelation and post-synthetic modification establish new strategies for nanoparticle assembly and provide a versatile platform for designing next-generation QD gel-based gas sensors and photocatalysts.

Bio: Dr. Long Luo is an Associate Professor of Chemistry at the University of Utah and leads the Luo Lab, an interdisciplinary research group focused on electrochemistry, catalysis, materials chemistry, organic synthesis, and chemical sensing. He earned his B.S. in Applied Chemistry from Beihang University (formerly Beijing University of Aeronautics and Astronautics) and his Ph.D. in Analytical Chemistry from the University of Utah. Following postdoctoral research with Prof. Richard Crooks at The University of Texas at Austin, he joined Wayne State University in 2017 before returning to Utah in 2024. 

Dr. Luo's research develops innovative electrochemical methods for chemical synthesis, energy conversion, catalysis, and sensing. His contributions have been recognized with numerous honors, including an NSF CAREER Award, an NIH MIRA Award, the Alfred P. Sloan Research Fellowship in Chemistry, the Royce W. Murray Young Investigator Award, and the 2025 Pittcon Achievement Award.