Mapping the Energy Carrier Diffusion Tensor in Perovskite Semiconductors.

Area of Science:

• Materials Science
• Solid State Physics
• Semiconductor Physics

Background:

• Understanding energy transport in semiconductors is vital for electronic and optoelectronic devices.
• Traditional methods often assume homogeneous materials, neglecting nanoscale structural complexities.
• Emerging semiconductors frequently exhibit heterogeneity, requiring advanced analysis techniques.

Purpose of the Study:

• To develop a high-resolution framework for analyzing energy transport in heterogeneous semiconductors.
• To quantify carrier transport and recombination in lead halide perovskites, considering their microstructure.
• To enable optimization of anisotropic energy transport in complex material systems.

Main Methods:

• Developed a diffusion tensor-based framework to analyze photoluminescence (PL) diffusion maps.
• Integrated spatial, temporal, and PL intensity data for global fitting.
• Applied the framework to single crystal and polycrystalline lead halide perovskites.

Main Results:

• Quantified carrier transport and recombination in heterogeneous lead halide perovskites.
• Revealed a 29% difference in principal diffusion coefficients between electronically coupled grains in CH3NH3PbI3 films.
• Demonstrated alignment between coupled grains influencing transport properties.

Conclusions:

• The developed framework accurately analyzes anisotropic energy transport in heterogeneous materials.
• Understanding microstructure-based transport is key for optimizing semiconductor device performance.
• This approach is applicable to various emerging heterogeneous semiconductor materials.