Defect Passivation: Physisorption or Chemisorption? A Nonadiabatic Molecular Dynamics Study.

Area of Science:

• Materials Science
• Solid-State Physics
• Photovoltaics

Background:

• Nonradiative charge recombination due to defects impedes semiconductor applications in solar energy.
• Defect passivation is a key strategy to mitigate recombination centers and improve efficiency.

Purpose of the Study:

• To investigate the impact of passivator adsorption configurations on defect passivation in InSe semiconductors.
• To understand the microscopic mechanisms governing photogenerated charge carrier dynamics after passivation.

Main Methods:

• Utilized nonadiabatic molecular dynamics (NAMD) simulations.
• Employed time-dependent density functional theory (TD-DFT) for accurate electronic structure calculations.

Main Results:

• Physisorption passivators failed to eliminate recombination centers, leading to rapid nonradiative charge recombination.
• Chemisorption passivators formed covalent bonds with indium, effectively removing recombination centers.
• Charge recombination time was extended by over tenfold with chemisorption passivators due to reduced nonadiabatic coupling.

Conclusions:

• Passivator adsorption configuration significantly influences defect passivation efficacy in InSe.
• Chemisorption passivators are essential for effective defect passivation, enhancing charge carrier dynamics for solar energy applications.