Custom Synthesis of ZnO Nanowires for Efficient Ambient Air-Processed Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Nanostructuration of solar cells is a key strategy for enhancing photovoltaic conversion efficiency (PCE).
• Developing advanced electron transport layers (ETLs) and efficient charge collection systems is crucial for high-performance photovoltaic devices.

Purpose of the Study:

• To engineer 3D hybrid photovoltaic solar cells utilizing ZnO nanowires (ZnONWs) as both ETL and electron nanocollectors within the active layer (AL).
• To optimize the morphology of ZnONWs and the assembly of the active layer for improved PCE.

Main Methods:

• Synthesis of ZnO nanowires (ZnONWs) via a hydrothermal process with controlled morphology.
• Fabrication of the active layer using a bulk heterojunction of PBDD4T-2F (donor) and PC71BM (acceptor) interpenetrated with ZnONWs.
• Optimization of assembly parameters including spin-coating temperature, donor/acceptor ratio, and pre/post-treatments.

Main Results:

• Successfully realized an interpenetrating 3D architecture of ZnONWs and the donor/acceptor blend with controlled morphology.
• Achieved a power conversion efficiency (PCE) of 7.7%, a 1.4-fold improvement over 2D cells.
• Demonstrated enhanced ZnO/AL interface area (6.6 μm²/μm² in 3D vs. 1 μm²/μm² in 2D) and efficient electron collection by ZnONWs within the active layer.

Conclusions:

• The 3D nanostructured architecture significantly boosts solar cell performance by increasing the active interface area and providing efficient electron pathways.
• The developed method validates the effectiveness of substrate nanotexturing and optimized assembly for high-efficiency hybrid organic solar cells.
• The study highlights the potential of using ZnONWs as integrated electron transport layers and nanocollectors in advanced photovoltaic devices.