Quantitative nanoscale surface voltage measurement on organic semiconductor blends.

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Polymer blend heterojunctions are crucial for organic electronics.
• Understanding nanoscale phase and work function variations is key to device performance.
• Existing methods for work function measurement can be complex and require specialized equipment.

Purpose of the Study:

• To validate a Kelvin probe force microscopy (KPFM) based method for nanoscale work function analysis of polymer blends.
• To demonstrate the method's capability without requiring ultra-high vacuum (UHV) conditions.
• To investigate the influence of processing conditions on the nanoscale properties of polymer blends.

Main Methods:

• Utilized Kelvin probe force microscopy (KPFM) for nanoscale surface potential measurements.
• Analyzed quantitative data from KPFM topography and Kelvin probe measurements.
• Investigated poly(3-hexyl-thiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) blends.

Main Results:

• Successfully validated KPFM for measuring different phases and relative work functions at the nanoscale.
• Observed distinct surface voltage differences at the nanoscale in P3HT:PCBM blends.
• Demonstrated that annealing conditions and the regio-regularity of P3HT affect the nanoscale work function.

Conclusions:

• KPFM offers a viable, accessible method for nanoscale work function characterization of polymer blends.
• The method provides quantitative insights into phase segregation and work function variations.
• Processing parameters significantly impact the nanoscale electronic properties of P3HT:PCBM blends, crucial for optimizing organic electronic devices.