Multiple electron transporting layers and their excellent properties based on organic solar cell

Area of Science:

• Materials Science
• Renewable Energy
• Organic Electronics

Background:

• Inverted polymer solar cells (PSCs) require efficient electron extraction for optimal performance.
• Ternary blends of PTB7:PC71BM:ICBA are promising active layers for PSCs.
• Interface engineering is crucial for enhancing charge transport and device efficiency.

Purpose of the Study:

• To enhance electron extraction in inverted PSCs by employing a ZnO/AZO nanoparticle bilayer.
• To investigate the impact of work function differences and energy level buffering on device performance.
• To further improve power conversion efficiency (PCE) through interface dipole engineering.

Main Methods:

• Fabrication of inverted PSCs utilizing a PTB7:PC71BM:ICBA ternary blend.
• Implementation of a ZnO/AZO nanoparticle bilayer as an electron transport layer.
• Characterization of device performance, including short circuit current, open circuit voltage, and PCE.
• Introduction of a ZnO/AZO/PFN trilayer for interface dipole modification.

Main Results:

• The ZnO/AZO bilayer demonstrated improved electron extraction compared to ZnO alone.
• Devices with the ZnO/AZO bilayer exhibited enhanced photocurrent and open circuit voltage, achieving a PCE of 8.85%.
• The ZnO/AZO/PFN trilayer further increased PCE to 9.17% by introducing an interface dipole.

Conclusions:

• A ZnO/AZO nanoparticle bilayer effectively enhances electron extraction and device performance in inverted PSCs.
• Energy level alignment and interface engineering are critical for maximizing PCE.
• The proposed interfacial strategies offer a pathway for developing high-efficiency organic solar cells.