Intrinsic Defect Physics in Indium-based Lead-free Halide Double Perovskites

Area of Science:

• Materials Science
• Solid-State Physics
• Renewable Energy

Background:

• Organic-inorganic halide perovskites face challenges due to instability and lead toxicity.
• Lead-free halide double perovskites (HDPs) are emerging as promising photovoltaic (PV) materials.
• Understanding defect and stability properties of HDPs is crucial for their PV applications.

Purpose of the Study:

• To systematically investigate the defect properties of HDPs using theoretical calculations.
• To identify optimal growth conditions for lead-free perovskite solar absorbers.
• To guide experimental fabrication of efficient lead-free perovskite solar cells.

Main Methods:

• First-principles theoretical calculations were employed.
• Stable chemical potential regions for stoichiometric Cs2AgInBr6 growth were determined.
• Defect properties under varying chemical potentials were analyzed.

Main Results:

• Stable growth regions for Cs2AgInBr6 without decomposition were identified.
• Ag-rich and Br-poor conditions favor n-type Cs2AgInBr6 with shallow defect levels.
• Conductivity of Cs2AgInBr6 can be tuned from n-type to intrinsic semiconducting.

Conclusions:

• Theoretical insights guide the fabrication of high-performance lead-free perovskite solar cells.
• Controlling chemical potential is key to optimizing Cs2AgInBr6 for PV applications.
• This study provides a roadmap for developing stable and efficient lead-free PV devices.