Field-Induced Transport Anisotropy in Single-Crystalline All-Inorganic Lead-Halide Perovskite Nanowires

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Halide perovskites exhibit coupled ion and electron transport, crucial for advanced semiconductor devices beyond solar cells.
• Microscale understanding of this coupled transport is limited by inhomogeneity in polycrystalline films.

Purpose of the Study:

• Investigate electric field-induced ionic transport in 1D single-crystalline cesium lead bromide (CsPbBr3) nanowires.
• Elucidate the origin of the giant switchable photovoltaic effect in these materials.

Main Methods:

• Utilized 1D single-crystalline CsPbBr3 nanowires for transport studies.
• Employed scanning photocurrent microscopy to map ionic transport.
• Used ultrafast scanning photoluminescence microscopy to analyze photocarrier dynamics.

Main Results:

• Demonstrated highly anisotropic ionic transport in CsPbBr3 nanowires after electrical poling.
• Identified accumulation of halogen vacancies as the cause of photocarrier localization.
• Observed a 10-fold increase in photoresponse speed due to enhanced local electric fields.

Conclusions:

• Established a link between anisotropic ionic transport and switchable photovoltaic effects.
• Showcased the potential of perovskite nanowires for submicrometer iontronic and optoelectronic devices.
• Highlighted the role of ion migration and vacancy accumulation in device performance.