Understanding the Heterointerfaces in Perovskite Solar Cells via Hole Selective Layer Surface Functionalization

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Interfaces in perovskite solar cells (PSCs) critically impact device performance through charge transport and recombination dynamics.
• Oxide-based transport layers in PSCs often suffer from defects, hindering optimal charge carrier management and overall efficiency.
• Surface passivation is crucial for mitigating these defects and improving the stability and performance of PSCs.

Purpose of the Study:

• To investigate the effectiveness of octadecylphosphonic acid (ODPA) for passivating the NiOₓ interface in PSCs.
• To enhance charge transport and reduce recombination at the hole transport layer (HTL)/perovskite interface.
• To achieve high-power conversion efficiency and hysteresis-free operation in PSC devices.

Main Methods:

• Surface passivation of NiOₓ using octadecylphosphonic acid (ODPA) as a self-assembly monolayer.
• Fabrication of PSC devices incorporating the ODPA-treated NiOₓ layer.
• Characterization of device performance, including power conversion efficiency and hysteresis analysis.
• Computational studies to explore the ODPA-treated HTL/Perovskite architecture.

Main Results:

• ODPA passivation significantly improved charge transport across the NiOₓ/perovskite interface.
• Achieved hysteresis-free PSC devices with an approximate 13% increase in power conversion efficiency.
• Demonstrated enhanced charge exchange capacity and reduced mid-gap energy states, leading to higher photogenerated carrier density.

Conclusions:

• ODPA surface functionalization is a viable strategy for enhancing the performance of NiOₓ-based PSCs.
• The findings support the broader application of phosphonic acid-based self-assembly monolayers for passivating oxide transport layers in PSCs.
• This research contributes to the development of highly efficient and stable halide perovskite solar cells.