Toughened Hybrid Electron-Transporting Interlayers for Efficient and Durable Organic Solar Cells

Area of Science:

• Materials Science
• Organic Electronics
• Renewable Energy

Background:

• Electron-transporting layers (ETLs) are critical components influencing organic solar cell (OSC) performance.
• Achieving both high efficiency and long-term stability in single-component ETLs for OSCs remains a significant challenge.
• The efficiency-stability trade-off is a major bottleneck in the commercialization of OSC technology.

Purpose of the Study:

• To develop novel hybrid ETLs using polyoxometalate (POM) doping to address the efficiency-stability trade-off in OSCs.
• To investigate the impact of tailored POM doping on the properties of hybrid ETLs.
• To demonstrate the potential of these hybrid interlayers for creating highly efficient and stable OSC devices.

Main Methods:

• Fabrication of hybrid ETLs by doping with polyoxometalates (POMs).
• Characterization of hybrid ETL properties, including energy-level alignment, conductivity, electrode adhesion, and aggregation.
• Fabrication and performance testing of OSC devices incorporating the developed hybrid ETLs.
• Stability testing of OSC devices under accelerated aging conditions (MPP tracking at elevated temperatures).

Main Results:

• POM-doped hybrid ETLs exhibited cascade energy-level alignment, enhanced conductivity, improved electrode adhesion, and suppressed self-aggregation.
• OSCs utilizing these hybrid ETLs achieved a power conversion efficiency of 20.4% and demonstrated outstanding operational stability (T93/T92 lifetime of 1500/1000 h at 40°C/65°C).
• Further optimization using PDIN-EME as an organic component in the hybrid ETL resulted in an elevated efficiency of 20.8% (20.4% certified) and a T90 lifetime of 1000 h.

Conclusions:

• Polyoxometalate (POM)-doped hybrid ETLs effectively mitigate the efficiency-stability trade-off in organic solar cells (OSCs).
• The tailored doping approach provides a versatile strategy for enhancing ETL properties, leading to high-performance and robust OSCs.
• These findings highlight the significant potential of hybrid interlayers for advancing the development of efficient and stable organic solar cell technologies.