Room-Temperature Oxygen Transport in Nanothin Bi x O y Se z Enables Precision Modulation of 2D Materials.

Oxygen conductors and transporters are important to several consequential renewable energy technologies, including fuel cells and syngas production. Separately, monolayer transition-metal dichalcogenides (TMDs) have demonstrated significant promise for a range of applications, including quantum computing, advanced sensors, valleytronics, and next-generation optoelectronics. Here, we synthesize a few-nanometer-thick Bi x O y Se z compound that strongly resembles a rare R 3 m bismuth oxide (Bi 2 O 3 ) phase and combine it with monolayer TMDs, which are highly sensitive to their environment. We use the resulting 2D heterostructure to study oxygen transport through Bi x O y Se z into the interlayer region, whereby the 2D material properties are modulated, finding extraordinarily fast diffusion near room temperature under laser exposure. The oxygen diffusion enables reversible and precise modification of the 2D material properties by controllably intercalating and deintercalating oxygen. Changes are spatially confined, enabling sub-micrometer features (e.g., pixels), and are long-term stable for more than 221 days. Our work suggests few-nanometer-thick Bi x O y Se z is a promising unexplored room-temperature oxygen transporter. Additionally, our findings suggest that the mechanism can be applied to other 2D materials as a generalized method to manipulate their properties with high precision and sub-micrometer spatial resolution.