Semiconductor Polymer/Top Electrode Interface Generated by Two Deposition Methods and Its Influence on Organic Solar...

Area of Science:

• Materials Science
• Energy Science
• Organic Electronics

Background:

• Organic photovoltaics (OPVs) offer a promising alternative to traditional solar cells.
• Efficient and cost-effective fabrication methods are crucial for OPV commercialization.
• Top-electrode deposition significantly impacts OPV performance and stability.

Purpose of the Study:

• To analyze the effect of two distinct top-electrode deposition techniques on OPV performance.
• To compare vacuum evaporation versus room-atmosphere deposition of Field's Metal (FM) electrodes.
• To evaluate the trade-offs between fabrication simplicity and device efficiency.

Main Methods:

• Fabrication of OPVs using ITO/PEDOT:PSS/PTB7-Th:PC71BM/PFN/top-electrode configuration.
• Deposition of top electrodes via high-vacuum evaporation (Ca/FM) and room-atmosphere melting/dripping (FM).
• Characterization using current-voltage measurements, atomic force microscopy (AFM), laser beam induced current (LBIC), and impedance analysis.

Main Results:

• Both deposition methods yielded similar average performance metrics (photocurrent density, open-circuit voltage, fill factor).
• Vacuum-evaporated electrodes achieved slightly higher average efficiency (6.4%) compared to room-atmosphere deposited electrodes (6.1%).
• Morphological analysis revealed surface inhomogeneities and pinholes in the room-atmosphere deposited FM electrodes, correlating with inhomogeneous photocurrent response and impedance defects.

Conclusions:

• Despite surface defects, the room-atmosphere deposition of FM electrodes is a viable, low-cost, and rapid alternative for OPV fabrication.
• The ease and vacuum-free nature of FM deposition highlight its potential for scalable OPV manufacturing.
• Further optimization of the room-atmosphere deposition process could mitigate interface defects and improve efficiency.