Enhanced performance using an SU-8 dielectric interlayer in a bulk heterojunction organic solar cell

Area of Science:

• Materials Science
• Organic Electronics
• Renewable Energy

Background:

• Organic solar cells (OSCs) offer a promising alternative for renewable energy generation.
• Interface engineering is crucial for optimizing the performance of bulk heterojunction (BHJ) OSCs.
• The zinc oxide (ZnO) electron transport layer and photoactive layer interface presents challenges in OSC fabrication.

Purpose of the Study:

• To investigate the impact of an SU-8 dielectric interlayer on inverted BHJ OSC performance.
• To analyze the effect of SU-8 on interfacial properties, carrier dynamics, and device stability.
• To understand the mechanisms behind efficiency enhancement in OSCs with an SU-8 interlayer.

Main Methods:

• Fabrication of inverted BHJ OSCs with and without an SU-8 interlayer.
• Characterization of device performance, including power conversion efficiency (PCE).
• Utilized transient photovoltage (TPV) and double injection (DoI) techniques to study carrier properties.

Main Results:

• Insertion of an ultrathin SU-8 layer created a smoother interface between ZnO and the photoactive layer.
• Devices with SU-8 exhibited a 14% enhancement in power conversion efficiency.
• SU-8 interlayers led to longer carrier lifetimes, increased mobility-lifetime (μ-τ) products, and improved device stability.

Conclusions:

• The SU-8 interlayer effectively reduces photogenerated carrier recombination without hindering charge transport.
• SU-8 integration enhances both the performance and operational stability of inverted BHJ OSCs.
• SU-8 represents a viable strategy for optimizing OSC interfaces and improving overall device characteristics.