Unlocking the Potential of Freestanding Borophene- Exploring its Reproducible Synthesis, Structure, and Properties
Abstract
Borophene, a two-dimensional boron sheet synthesized on Ag substrates in 2015, has garnered extensive scientific attention. With its remarkable chemical and structural complexity, tunable bandgap, massless Dirac fermions, high carrier mobility, super hardness, and superconductivity, borophene exhibits unique chemical and physical properties that hold significant promise for applications e.g., in quantum computing, thermoelectrics, batteries, hydrogen storage, supercapacitors, sensors, and catalysis. However, the current limitations of template-assisted synthesis techniques hinder in-depth investigations and widespread applications of borophene. This project focuses on the utilization of layered metal borides (LMBs) as promising precursors for freestanding borophene synthesis. A comprehensive understanding of the structural characteristics of initial LMBs and their correlation with the resulting borophene motifs is essential for developing effective synthesis methodologies and tailoring borophene properties. Our primary objective is the achievement of reproducible synthesis for single or few-layered boron nanosheets (BNSs) through two innovative approaches involving the controlled removal of metal atoms between the borophene units of LMBs. These methodologies integrate ultrasound-assisted exfoliation with (i) ion-exchange and (ii) redox reactions using gaseous HCl and Lewis acids. Complementary computational studies will provide insights into the structural transformation of LMBs into borophene during the synthesis process. To investigate the chemical properties and crystal structure of various borophene allotropes, advanced techniques will be employed including X-ray diffraction (XRD), scanning tunneling microscopy (STM), atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), inductively coupled plasma-mass spectroscopy (ICP-MS), Fourier Transform Infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). These analyses will enable assessing synthesized borophene s quality, structure (including defects), and chemical properties, offering valuable insights for further optimization. Our research will also explore borophene s electronic and mechanical properties through a combination of experimental tools and theoretical calculations. By utilizing conductive atomic force microscopy (c-AFM) and STM, we will furnish crucial nanoscale details on electronic conductivity behavior. Angle-resolved photoemission spectroscopy (ARPES) will facilitate direct observation and in-depth analysis of borophene s electronic attributes, unveiling its band structure, electronic states, and Fermi surface. We will perform nanoindentation measurements to assess borophene s hardness, stiffness, and elastic modulus. We will employ effective strategies involving metal atom doping and surface functionalization to mitigate stability issues for borophene and tune its electronic properties. After succeeding reproducible production of stable borophene, its integration with other two-dimensional (2D) materials like transition metal dichalcogenides will be pursued to create heterostructures with unique properties.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 05, 2025
- Source ID
- FA86552417389
Entities
People
- Umut Aydemir
Organizations
- Air Force Office of Scientific Research
- United States Air Force