Self-Limiting Ultrathin Heterocycle-Bridged Interface Enabling Efficient p-i-n PbS Quantum Dot Solar Cells

Area of Science:

• Materials Science
• Nanotechnology
• Photovoltaics

Background:

• Self-assembled monolayers (SAMs) are crucial for improving solar cell efficiency.
• Efficient electron extraction is vital for device performance, but electron-transporting SAMs are underdeveloped.
• Lead sulfide (PbS) quantum dot (QD) solar cells offer potential for low-cost, high-performance photovoltaics.

Purpose of the Study:

• To develop an effective electron-extraction-modulating strategy for PbS QD solar cells.
• To design ultrathin molecular layers that enhance interfacial properties.
• To overcome limitations in electron extraction for improved device performance.

Main Methods:

• Designed thiophene-based molecules with thiol anchors for coordination with Pb2+ ions.
• Utilized π-π interactions between the molecules and C60 layer to improve electron extraction.
• Employed a self-limiting, volatile molecular layer strategy for interface modification.

Main Results:

• Achieved a power conversion efficiency of 14.47% in p-i-n PbS QD solar cells, a new record.
• Demonstrated suppression of nonradiative recombination through molecular coordination.
• Enhanced electron extraction via π-π interactions at the interface.

Conclusions:

• The self-limiting ultrathin molecular layer strategy is a powerful method for interfacial design in QD solar cells.
• This approach offers a robust and scalable pathway for improving solar cell performance.
• The developed strategy significantly advances the efficiency of p-i-n PbS QD solar cells.