Tunable Ferroelectricity in Ruddlesden-Popper Halide Perovskites

Area of Science:

• Materials Science
• Solid-State Physics
• Renewable Energy

Background:

• Ruddlesden-Popper (RP) halide perovskites offer high performance and stability in photovoltaics.
• Their layered structure presents opportunities for ferroelectric applications.
• Understanding the structure-function relationship of RP ferroelectricity is crucial.

Purpose of the Study:

• To achieve tunable ferroelectricity in (PEA)2(MA)n-1Pb nI3n+1 RP perovskites.
• To investigate the underlying mechanisms of ferroelectric behavior.
• To explore the implications for optoelectronic applications.

Main Methods:

• Synthesis of (PEA)2(MA)n-1Pb nI3n+1 RP perovskite thin films.
• Second harmonic generation (SHG) for noncentrosymmetry confirmation.
• Piezoresponse force microscopy and P-E loop measurements for ferroelectricity validation.
• Temperature-dependent SHG and dielectric measurements.
• Molecular dynamics simulations.

Main Results:

• Tunable ferroelectricity was successfully realized in the studied RP perovskites.
• SHG, PFM, and P-E loops confirmed noncentrosymmetric and ferroelectric properties.
• A phase transition temperature of ~170 °C was identified.
• Molecular dynamics simulations revealed MA reorientation and ion translation as the source of ferroelectricity.
• Hysteresis was observed in current-voltage characteristics.

Conclusions:

• Engineering ferroelectric properties in RP perovskites is achievable.
• The findings provide insights into the mechanisms of ferroelectricity in these materials.
• The observed ferroelectric properties have significant potential for light-harvesting and light-emitting applications in perovskite optoelectronics.