Optimizing scalable synthesis of high-quality FeSe quantum dot in organic and aqueous states

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 473; p. 145034
• Main Authors: Kang, Hyojin, Choi, Yujin, Wei, Mengqi, Kwon, Junyoung, Nguyen, Huu-Quang, Lee, Seoungyun, Kim, Kyungmin, Lee, Minsu, Lee, Jaebeom
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2023
• Subjects: Aqueous and organic synthesis; Iron selenide; Phase transition; Production yield; Quantum yield; Scale-up; Aqueous and organic synthesis; Quantum yield; Production yield; Iron selenide; Scale-up; Phase transition
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.145034

•Synthesis of FeSe quantum dots with unique multicolored excitation dependent emission.•Environmentally-friendly mass production of biocompatible, non-toxic FeSe quantum dots.•The scale-up method of quantum dots allows their use in various industrial fields. A typical layered transition metal chalcogenide nanostructure, FeSe quantum dots (QDs) have recently begun to attract for their unique optical properties, i.e., multicolored excitation dependent emission (MEDE) property that breaks conventional Kasha - Vavilov rule as well as their potential applications in biological, and optical/electronic sensing and imaging. In this article, we present robust and optimized protocols for the scalable synthesis of FeSe QDs either in aqueous or organic syntheses. The synthesis conditions were carefully compared to obtain insistent synthesis parameters, e.g., solvents, precursors, stabilizers, pH, temperature, concentration, and reaction time after reproduction experiments. Furthermore, post-treatment procedures, i.e., phase transition and PEGylation are also optimized for further potential environmental and biological applications. In the scale-up experiments, a 5-liter reactor was utilized to produce approximately 55 g of QDs per batch, showing a robust optical MEDE property. The most optimized experimental condition reached quantum yield (QY) up to 60 % at the typical synthesis conditions of pH 9.0, 95 °C for 4 h of reflux, and the production yield of ca. 20%. These high fluorescent QDs can be potentially applied for biological fluorophores as well as next-generation QD displays.