Intrinsic defects in B-site columnar-ordered halide double perovskites Cs₂AgPdBr₅

Area of Science:

• Materials Science
• Solid-State Physics
• Photovoltaics

Background:

• Cesium silver palladium bromide (Cs2AgPdBr5) is a novel double perovskite with potential for photovoltaic applications.
• Intrinsic defects significantly influence the electronic properties and performance of semiconductor materials.
• Understanding defect behavior is critical for optimizing Cs2AgPdBr5 for solar energy conversion.

Purpose of the Study:

• Investigate the intrinsic defect properties of Cs2AgPdBr5 using first-principles calculations.
• Determine the phase diagram and thermodynamic stability of Cs2AgPdBr5.
• Identify key defects and their impact on charge carrier behavior for photovoltaic applications.

Main Methods:

• First-principles calculations were employed to study defect properties.
• Phase diagrams were computed to assess thermodynamic stability.
• Fermi-level pinning and deep-level recombination centers were systematically analyzed.

Main Results:

• The thermodynamic stable region for Cs2AgPdBr5 is narrow, requiring controlled synthesis conditions.
• p-type conductivity can be achieved under silver-poor conditions.
• Palladium interstitials (Pd2+i) and palladium-antimony antisites (Pd1+Ag) are identified as the primary deep-level recombination centers at 300 K.

Conclusions:

• Careful control of growth conditions and stoichiometry, particularly minimizing palladium content, is essential for high-quality Cs2AgPdBr5.
• The identified defects and synthesis guidance are crucial for developing high-performance Cs2AgPdBr5-based photovoltaic devices.