Dimensionality-dependent electronic and vibrational dynamics in low-dimensional organic-inorganic tin halides

Area of Science:

• Materials Science
• Solid State Physics
• Photochemistry

Background:

• Photo-induced electronic processes depend on electron-nuclear interactions.
• Organic-inorganic metal halides are promising materials for optoelectronic applications.
• Controlling exciton dynamics is key to material performance.

Purpose of the Study:

• Investigate how material dimensionality influences exciton-phonon coupling and self-trapping.
• Elucidate the role of Anderson localization in one-dimensional systems.
• Identify specific vibrational modes responsible for exciton self-trapping.

Main Methods:

• Fabrication of one- and two-dimensional organic-inorganic tin halides.
• Femtosecond transient absorption spectroscopy.
• Theoretical analysis of exciton dynamics and localization.

Main Results:

• One-dimensional systems show strong exciton-phonon coupling and excitation-independent self-trapped exciton emission.
• Two-dimensional systems exhibit significantly weaker coupling, leading to free exciton emission.
• Room-temperature vibrational wavepackets, including wagging and asymmetric stretching modes in tin iodide (~106 cm⁻¹), were observed in 1D systems, driving exciton self-trapping.

Conclusions:

• Material dimensionality strongly dictates exciton-phonon coupling and self-trapping behavior.
• Enhanced Anderson localization in 1D systems promotes exciton self-trapping.
• Understanding these dynamics provides guidance for designing advanced metal halide materials.