Implementation of data-cube pump-probe KPFM on organic solar cells

Area of Science:

• Surface science
• Nanoscale characterization
• Photovoltaics

Background:

• Kelvin probe force microscopy (KPFM) is a powerful technique for measuring surface potential.
• Time-resolved measurements are crucial for understanding dynamic processes in materials.

Purpose of the Study:

• To implement and validate a pump-probe Kelvin probe force microscopy (pp-KPFM) technique.
• To investigate the dynamical photoresponse of organic solar cells.

Main Methods:

• Development of an open z-loop pp-KPFM system for simplified operation.
• Acquisition of time-resolved surface potential data in single-point and 2D grid modes.
• Electrical pumping for method validation and photoresponse studies on PTB7:PC71BM solar cells.

Main Results:

• Successful implementation of pp-KPFM enabling time-resolved surface potential mapping.
• Demonstration of the technique's validity through electrical pumping experiments.
• Investigation of the dynamical photoresponse and surface photovoltage in organic active layers.

Conclusions:

• The developed pp-KPFM technique is effective for time-resolved surface potential measurements.
• The method provides insights into the photoresponse dynamics of organic photovoltaic materials.
• This work advances nanoscale characterization for energy conversion devices.