Zinc Oxide-Perylene Diimide Hybrid Electron Transport Layers for Air-Processed Inverted Organic Photovoltaic Devices

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic photovoltaics (OPVs) require efficient electron transporting layers (ETLs) for optimal performance.
• Developing ETLs from sustainable, green solvents is crucial for environmentally friendly device fabrication.
• Perylene diimide (PDI) derivatives offer promising electronic properties but often require harsh solvents for processing.

Purpose of the Study:

• To develop solution-processable PDI-based ETLs using green solvents.
• To investigate the properties of these PDI films and their impact on inverted-type organic photovoltaics.
• To enhance the power conversion efficiency (PCE) of organic solar cells.

Main Methods:

• Synthesis of a modified N-annulated PDI with a protecting group for solubility in green solvents.
• Fabrication of PDI films via solution processing and post-deposition thermal annealing to remove the protecting group.
• Characterization of PDI films using optical absorption spectroscopy, contact angle measurements, and atomic force microscopy.
• Integration of PDI films as ETLs with ZnO in inverted-type OPVs based on PM6:Y6 and PTQ10:Y6 bulk-heterojunctions.

Main Results:

• Successfully formed PDI films from green solvents.
• The post-deposition annealing rendered the PDI films solvent-resistant.
• Incorporation of PDI films as ETLs improved the PCE of inverted OPVs.
• Device PCE increased from 9.8% to 11.0% for PM6:Y6 and from 7.2% to 9.8% for PTQ10:Y6.

Conclusions:

• The developed PDI films are effective ETLs for inverted-type organic photovoltaics.
• Green solvent processing of PDI materials is feasible and beneficial for OPV fabrication.
• The PDI/ZnO interface modification significantly boosts device performance and power conversion efficiency.