Reversible Electrochemical Gelation of Metal Chalcogenide Quantum Dots

• Published in: Journal of the American Chemical Society Vol. 142; no. 28; pp. 12207 - 12215
• Main Authors: Hewa-Rahinduwage, Chathuranga C, Geng, Xin, Silva, Karunamuni L, Niu, Xiangfu, Zhang, Liang, Brock, Stephanie L, Luo, Long
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 15.07.2020
• Subjects: air quality; ambient temperature; Cadmium Compounds - chemical synthesis; Cadmium Compounds - chemistry; cadmium sulfide; Electrochemical Techniques; electrochemistry; electronic equipment; gelation; gels; Gels - chemical synthesis; Gels - chemistry; monitoring; nitrogen dioxide; Particle Size; quantum dots; Quantum Dots - chemistry; Selenium Compounds - chemical synthesis; Selenium Compounds - chemistry; Sulfides - chemical synthesis; Sulfides - chemistry; Surface Properties; Zinc Compounds - chemical synthesis; Zinc Compounds - chemistry; zinc sulfide
• ISSN: 0002-7863; 1520-5126; 1520-5126
• DOI: 10.1021/jacs.0c03156

The ability to dictate the assembly of quantum dots (QDs) is critical for their integration into solid-state electronic and optoelectronic devices. However, assembly methods that enable efficient electronic communication between QDs, facilitate access to the reactive surface, and retain the native quantum confinement characteristics of the QD are lacking. Here we introduce a universal and facile electrochemical gelation method for assembling metal chalcogenide QDs (as demonstrated for CdS, ZnS, and CdSe) into macroscale 3-D connected pore-matter nanoarchitectures that remain quantum confined and in which each QD is accessible to the ambient. Because of the redox-active nature of the bonding between QD building blocks in the gel network, the electrogelation process is reversible. We further demonstrate the application of this electrogelation method for a one-step fabrication of CdS gel gas sensors, producing devices with exceptional performance for NO2 gas sensing at room temperature, thereby enabling the development of low-cost, sensitive, and reliable devices for air quality monitoring.