Dual-site mixed layer-structured FA Cs_3- Sb₂I₆Cl₃ Pb-free metal halide perovskite solar cells

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photovoltaics

Background:

• Trivalent metal halide perovskites (MHPs) with the formula A3Sb2X9 are being explored for solar cell applications.
• The electronic properties of MHPs are strongly influenced by their crystal structure, with 2D layered structures exhibiting narrower bandgaps than 0D dimer structures.
• Controlling the structure of MHPs is crucial for optimizing their optoelectronic properties.

Purpose of the Study:

• To engineer the structure of trivalent metal halide perovskites (MHPs) for improved solar cell performance.
• To investigate the effect of dual-site (A and X site) mixing on the crystal structure and properties of MHPs.
• To demonstrate a 2D layered MHP structure with enhanced photovoltaic characteristics.

Main Methods:

• Dual-site mixing of monovalent cations (formamidinium, cesium) and halogens (iodine, chlorine) on the A and X sites, respectively.
• Synthesis of FACs2Sb2I6Cl3 MHP with a targeted 2D layered structure.
• Fabrication and characterization of MHP solar cells to evaluate performance.

Main Results:

• Successfully synthesized a 2D layered FACs2Sb2I6Cl3 MHP through dual-site mixing.
• Observed a change in lattice symmetry due to I-Cl mixed halide composition.
• Achieved improved short-circuit current density in MHP solar cells due to the 2D layered structure.

Conclusions:

• Dual-site mixing is an effective strategy for controlling the structure of MHPs.
• The 2D layered structure of FACs2Sb2I6Cl3 MHP leads to enhanced photovoltaic performance.
• Further research into structure-property relationships in MHPs can unlock their full potential for solar energy conversion.