Strain-Driven Solid-Solid Crystal Conversion in Chiral Hybrid Pseudo-Perovskites with Paramagnetic-to-Ferromagnetic...

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• Hybrid organic-inorganic perovskites (HOIPs) are stimuli-responsive materials (SPMs) with tunable properties.
• Understanding strain-induced structural changes in HOIPs is crucial for designing mechanically responsive materials.
• The role of chirality in strain-induced phase conversion within HOIPs remains unexplored.

Purpose of the Study:

• To investigate the effect of mechanical strain on chiral halide perovskite single crystals.
• To explore the potential of chiral organic cations in mediating strain-induced structural transformations.
• To demonstrate a novel crystal-to-crystal conversion driven by mechanical stress.

Main Methods:

• Synthesis of chiral halide pseudo-perovskite single crystals (R/S)-(FE)2CuCl4.
• Application of mechanical strain to induce solid-phase crystal conversion.
• Characterization of structural changes using X-ray diffraction and other spectroscopic techniques.
• Control experiments with achiral and racemic analogs.

Main Results:

• Mechanical strain induced a phase conversion from 0D CuCl4 tetrahedra to a 1D CuFCl5 octahedral framework in chiral perovskites.
• This conversion involved Cu-F interactions and N-H-F hydrogen bonding, altering physical properties like band gap and magnetic behavior.
• Achiral or racemic analogs did not exhibit this strain-induced solid-phase conversion.
• The material was successfully integrated into a pressure-sensitive display on Spandex substrates.

Conclusions:

• Chiral organic cations provide a unique pathway for controlling strain-induced phase transitions in HOIPs.
• This study reveals a new mechanism for mechanical response in perovskite materials.
• The developed material demonstrates potential for large-scale applications in pressure-sensing technologies.