Giant Band Gap Narrowing under Hydrostatic Pressure in (4FP)₂SnI₄ Halide Perovskite

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid-State Chemistry

Background:

• Hybrid halide perovskites possess unique structural softness due to organic-inorganic sublattice interactions.
• This structural property enables phenomena uncommon in traditional semiconductors, such as significant band gap tunability under hydrostatic pressure.
• Tin-based perovskites demonstrate a more pronounced pressure-induced band gap shift compared to lead-based counterparts.

Purpose of the Study:

• To investigate and report one of the largest observed band gap tunabilities within the tin-based perovskite family.
• To characterize the pressure-dependent band gap behavior of the layered tin-based (4FP)2SnI4 perovskite.
• To evaluate the potential of (4FP)2SnI4 for pressure-sensing technologies.

Main Methods:

• Experimental synthesis and characterization of layered tin-based (4FP)2SnI4 perovskite.
• Hydrostatic pressure application and in-situ measurement of band gap shifts.
• Computational modeling to understand the pressure-induced electronic structure changes.

Main Results:

• The layered tin-based (4FP)2SnI4 perovskite exhibits exceptionally strong pressure sensitivity.
• A substantial band gap shift of up to -160 meV/GPa was recorded at room temperature.
• The band gap dependence on pressure was found to be linear within the 0-5 GPa range.

Conclusions:

• The exceptional and linear pressure sensitivity of (4FP)2SnI4 positions it as a highly attractive material for pressure-sensor applications.
• The findings contribute to the understanding of structure-property relationships in hybrid perovskites under external stimuli.
• This research highlights the potential of tin-based perovskites for optoelectronic devices requiring high pressure responsiveness.