Inverted Organic Solar Cells Enabled by a ZnO/Organic Electrolyte Dual-Layer Electron Transport Layer with Improved...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Zinc oxide (ZnO) is a key cathode interface material in inverted organic solar cells (I-OSCs).
• Surface defects in ZnO limit the efficiency and operational lifetime of I-OSCs.
• Current surface modification methods are often too thin for industrial-scale production.

Purpose of the Study:

• To develop a scalable surface modification strategy for ZnO films in I-OSCs.
• To investigate the impact of small-molecule electrolytes (SMEs) on ZnO film properties and device performance.
• To enhance the efficiency and stability of I-OSCs through defect passivation.

Main Methods:

• Surface modification of ZnO films using two SMEs: PMABr and PMABr-OH.
• Fabrication and characterization of inverted organic solar cells (I-OSCs) with modified ZnO electron transport layers (ETLs).
• Investigation of the effects of modification layer thickness on device performance.

Main Results:

• PMABr-OH modification passivated oxygen vacancy defects in ZnO, improving device efficiency from 15.90% to 17.02%.
• Modified ETLs enhanced the stability of I-OSC devices compared to the reference.
• Thick-film I-OSCs (10-35 nm modification layers) achieved power conversion efficiencies (PCEs) over 16.6%.

Conclusions:

• SMEs like PMABr-OH offer an effective and scalable method for ZnO surface modification in I-OSCs.
• This approach significantly improves both the efficiency and stability of organic photovoltaic devices.
• The developed dual-layer ETL is suitable for industrial fabrication and contributes to carbon reduction.