A Double Perovskite Single Crystal CsCuAgI₃

Area of Science:

• Materials Science
• Solid-State Physics
• Photovoltaics

Background:

• Traditional lead-based halide perovskites face environmental concerns.
• Eco-friendly alternatives with suitable band gaps are needed.
• Current lead-free double perovskites often have wide or indirect band gaps.

Purpose of the Study:

• To synthesize and characterize a novel, eco-friendly, all-inorganic CsCuAgI3 single crystal.
• To investigate its optoelectronic properties for potential applications.
• To evaluate its suitability as a substitute for lead-based perovskites.

Main Methods:

• Synthesis of millimeter-scale CsCuAgI3 single crystals.
• Optical characterization using absorption and photoluminescence spectroscopy.
• Fabrication and testing of a photoelectric detection prototype.

Main Results:

• A direct band gap of 2.02 eV at the G-point was achieved.
• High Urbach energy (119 meV) indicates significant structural disorder.
• Demonstrated a wide Stokes shift (230 nm), broad fwhm (152 nm), and long fluorescence lifetime (7.29 μs).
• The CsCuAgI3 prototype exhibited a sensitive photoelectric response (0.37/0.21 s).

Conclusions:

• CsCuAgI3 is a promising lead-free double perovskite with advantageous optoelectronic properties.
• Its direct band gap and stability make it suitable for photoelectric devices.
• This research paves the way for novel lead-free perovskite development.