Hexagonal Boron Nitride Nanosheets Protect Exfoliated Black Phosphorus Layers from Ambient Oxidation

Author(s)

Pravda, Cora Bartus ; Hegedus, Timea ; Oliveira, Eliezer Fernando ; Berkesi, Daniel ; Szamosvolgyi, Akos ; Konya, Zoltan ; Vajtai, Robert ; Kukovecz, Akos

• Document type: Journal article
• Source: ADVANCED MATERIALS INTERFACES; v. 9, n. 24, p. 8-pg., 2022-07-20.

Abstract

Black phosphorus-based 2D materials have yet to demonstrate their full application potential because of the well-known sensitivity of phosphorene to spontaneous oxidation under ambient conditions. It is hypothesized that this unfavorable process can be prevented by drop-casting hexagonal boron nitride (h-BN) nanosheets on phosphorene. Here, both materials are prepared by sonication-assisted liquid-phase exfoliation of bulk materials and characterized by transmission electron microscopy and Raman spectroscopy. Raman spectroscopy is also utilized for the real-time monitoring of phosphorene oxidation by calculating the A(1g)/A(2g) intensity ratio. This value drops below 0.5 (corresponding to complete oxidation) within 100 min for pristine phosphorene layers in the air. However, it remains constant above 0.6 (indicating no oxidation) when phosphorene covered by h-BN sheets is left in the air. Moreover, deploying h-BN sheets at midterm during the ambient oxidation reaction is able to halt the process and maintain a steady 0.5 < A(1g)/A(2g) < 0.6 Raman intensity ratio. The experimental results are successfully interpreted within the developed theoretical framework by the charge distribution of h-BN, which keeps O-2 molecules from interacting with its surface, and the fact that the first O-2 molecules in contact react with the edges of h-BN, thus creating a barrier for subsequently arriving O-2 molecules. (AU)

• FAPESP's process: 19/07157-9 - DESIGNING NEW 3D STRUCTURES FROM ZEOLITE TEMPLATES FOR 3D PRINTING APPLICATIONS
• Grantee: Eliezer Fernando de Oliveira
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 13/08293-7 - CCES - Center for Computational Engineering and Sciences
• Grantee: Munir Salomao Skaf
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 16/18499-0 - Investigation on the structural, mechanical and functional properties of carbon-based nanostructures
• Grantee: Eliezer Fernando de Oliveira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral