Solvent-assisted mechanochemical crystallization of the metal-free perovskite solid solution (H₂dabco,...

Area of Science:

• Materials Science
• Crystallography
• Solid-State Chemistry

Background:

• Metal-free perovskites offer tunable properties for various applications.
• Understanding molecular dynamics in solid solutions is crucial for predicting material behavior.
• Previous studies on (d,h)-BF4 have not fully explored the compositional dependence of molecular dynamics.

Purpose of the Study:

• To synthesize and characterize all-proportional solid solutions of (H2dabco1-y, H2hmta_y)(NH4)(BF4)3.
• To investigate the influence of composition (y) on the molecular dynamics of these solid solutions.
• To determine the compositional boundary for dynamic disorder in H2dabco2+.

Main Methods:

• Mechanochemical crystallization of (d,h)-BF4 solid solutions.
• Analysis of molecular dynamics as a function of composition (y).
• Identification of phase transition temperatures and states of molecular disorder.

Main Results:

• All-proportional solid solutions of (d,h)-BF4 were successfully synthesized.
• Molecular dynamics were found to be dependent on the composition ratio (y).
• A compositional boundary at y = 0.43 was identified, beyond which H2dabco2+ exhibits dynamic disorder even below the plastic crystalline phase transition temperature observed at y = 0.

Conclusions:

• The study demonstrates tunable molecular dynamics in metal-free perovskite solid solutions through compositional control.
• H2dabco2+ undergoes dynamic disorder at specific compositions, influencing the material's phase behavior.
• Mechanochemical synthesis provides an effective route for creating these functional solid solutions.