Facile and accelerated production of RuO2 monolayers via a dual-step intercalation process

• Published in: Inorganic chemistry frontiers Vol. 7; no. 6; pp. 1445 - 1450
• Main Authors: Se Yun Kim, Weon Ho Shin, Doh Won Jung, Dong-Su, Ko, Roh, Jong Wook, Hwang, Sungwoo, Lee, Jongmin, Lee, Kimoon, Hee Jung Park, Kwak, Chan, Kim, Sang-il, Jeong, Hyung Mo, Lee, Kyu Hyoung, Kim, Hyun Sik
• Format: Journal Article
• Language: English
• Published: London Royal Society of Chemistry 21.03.2020
• Subjects: Density functional theory; Exfoliation; Inorganic chemistry; Intercalation; Ion exchange; Metal oxides; Monolayers; Optoelectronics; Organic chemistry; Ruthenium oxide
• ISSN: 2052-1545; 2052-1553
• DOI: 10.1039/c9qi01678c

Tetrabutylammonium ions (TBA+) have commonly been used to exfoliate RuO2 into monolayers via ion exchange reactions. However, the low production yield of RuO2 exfoliation, which originates from the large molecular size of TBA+, limits wider utilisation of RuO2 monolayers in optoelectronic applications. We introduce a rapid and efficient dual-step exfoliation process beginning with intercalation of small organic molecules (tetramethylammonium ions) into RuO2, which is followed by the addition of TBA+ as a second intercalant to realize RuO2 monolayer production. Our dual-step intercalation process increases the RuO2 monolayer exfoliation yield from 9.9% to 60% after 14 days. Density functional theory calculations reveal that the activation energy of dual-step intercalation is much lower than that of direct intercalation of TBA+ ions into the RuO2 structure. The experimental and theoretical results of dual-step intercalation suggest that it is a facile and general approach for the production of metal oxide monolayers, and could widen the use of metal oxide monolayer nanosheets.