Tuning the work function of nickel oxide using triethoxysilane functionalized monolayers.

Area of Science:

• Materials Science
• Surface Chemistry
• Condensed Matter Physics

Background:

• Nickel oxide (NiOx) is a widely used p-type semiconductor material.
• Tuning the work function of electrodes is crucial for optimizing device performance in organic electronics and catalysis.
• Controlling surface properties at the molecular level offers a pathway to engineer material characteristics.

Purpose of the Study:

• To investigate the covalent attachment of functionalized molecules to NiOx surfaces.
• To tune the work function of NiOx electrodes by modifying their surface properties.
• To establish a correlation between molecular dipole moments and work function changes.

Main Methods:

• Covalent attachment of triethoxysilane functionalized molecules with varying dipole moments to NiOx surfaces.
• Surface characterization using Fourier Transform Infrared (FTIR) spectroscopy and contact angle measurements.
• Work function measurements using Kelvin probe technique.
• Theoretical calculations using Density Functional Theory (DFT) to determine molecular dipole moments.

Main Results:

• Successful covalent attachment of molecular layers onto NiOx surfaces, verified by FTIR and contact angle measurements.
• Significant tuning of the NiOx work function, with changes up to approximately 900 meV.
• Demonstrated correlation between the dipole moments of the attached molecules and the observed work function shifts.
• Incomplete surface coverage was sufficient to induce substantial work function modulation.

Conclusions:

• Molecular functionalization provides an effective strategy for tuning the work function of NiOx electrodes.
• The magnitude of work function change is predictable based on the molecular dipole moment.
• This approach offers precise control over electrode properties for advanced electronic applications.