X-Ray Nanoscopy of a Bulk Heterojunction

Area of Science:

• Materials Science
• Condensed Matter Physics
• Renewable Energy

Background:

• Optimizing bulk heterojunction morphology is crucial for organic solar cell (OSC) performance.
• Existing quantitative imaging techniques for OSCs have limitations.
• Understanding nanoscale morphology is key to improving device efficiency.

Purpose of the Study:

• To demonstrate X-ray ptychographic coherent diffractive imaging for all-organic blends.
• To image the phase-separated morphology in OSC photoactive layers.
• To monitor nano-morphological changes during thermal annealing.

Main Methods:

• X-ray ptychographic coherent diffractive imaging applied to P3HT:PCBM blends.
• Utilizing a fast-scanning calorimetry chip for in-situ monitoring.
• High-resolution imaging of phase-segregated domains.

Main Results:

• Achieved resolution better than 100 nm for phase-segregated domains.
• Quantitatively estimated local volume fraction of PCBM.
• Observed nano-morphological changes due to thermal annealing and PCBM diffusion.

Conclusions:

• X-ray ptychography is a powerful tool for high-resolution imaging of organic-organic blends.
• The technique provides insights into morphology and material diffusion.
• Promising for future in-situ studies of OSCs and structural stability.