Atomic-Scale Model and Electronic Structure of Cu₂O/CH₃NH₃PbI₃ Interfaces in Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Semiconductor Physics

Background:

• Hybrid halide perovskite solar cells offer high potential for renewable energy.
• Traditional organic hole-transport layers face limitations.
• Cuprous oxide (Cu2O) is explored as an alternative, but its interface with perovskites requires detailed understanding.

Purpose of the Study:

• To investigate the atomistic and electronic properties of the CH3NH3PbI3/Cu2O interface.
• To identify interface configurations that enhance photovoltaic performance.
• To provide insights for improving experimental device fabrication.

Main Methods:

• Density functional theory (DFT) calculations were employed.
• Several atomistic models of the Cu2O/perovskite interface were constructed.
• Electronic properties, including band alignment, adhesion energy, and charge transfer, were analyzed.

Main Results:

• Novel atomistic models of the Cu2O/CH3NH3PbI3 interface were developed.
• Formation of vacancies in Cu2O terminating planes is crucial for eliminating trap states.
• Four interface models with favorable band alignment for photovoltaics were identified.
• Termination of CH3NH3PbI3 with PbI2 planes appears optimal for maximizing photoconversion efficiency.

Conclusions:

• The study provides fundamental insights into the Cu2O/perovskite interface.
• Interface engineering, specifically vacancy formation and termination, is critical for efficient perovskite solar cells.
• The findings guide experimental efforts towards realizing high-performance Cu2O-based devices.