Decreasing the electronic confinement in layered perovskites through intercalation

Area of Science:

• Materials Science
• Solid-State Physics
• Quantum Chemistry

Background:

• Two-dimensional (2D) hybrid perovskites offer tunable optoelectronic properties but suffer from strong electronic confinement.
• Reducing exciton binding energy is crucial for improving charge carrier mobility and device performance.

Purpose of the Study:

• To investigate the impact of post-synthetic small-molecule intercalation on the electronic confinement of 2D hybrid perovskites.
• To elucidate the structural, optical, and electronic effects of intercalating polarizable molecules.
• To develop a computational method for evaluating exciton binding energy in these materials.

Main Methods:

• Combined experimental and theoretical approaches.
• Post-synthetic small-molecule intercalation.
• Calculation of spatially resolved dielectric profiles.
• Solving the Bethe-Salpeter equation for exciton binding energy with ab initio dielectric profiles.

Main Results:

• Intercalation of polarizable molecules significantly reduces electronic confinement in 2D hybrid perovskites.
• Organic layers become more polarizable than inorganic layers after intercalation.
• Achieved the lowest reported exciton binding energy for an n=1 perovskite.
• Developed a novel semi-empirical method for exciton binding energy calculation.

Conclusions:

• Post-synthetic intercalation of polarizable molecules is an effective strategy for tuning 2D perovskites.
• This approach reduces exciton confinement, mimicking 3D perovskites while retaining synthetic tunability.
• The developed computational method provides accurate exciton binding energy evaluation, surpassing phenomenological approximations.