A P-Type Organic Dye as Interface Layer for Efficient and Stable Inverted Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Nickel oxide (NiO_x) is a key hole-transport material in inverted perovskite solar cells (PSCs).
• Light-induced degradation at the NiO_x-perovskite interface limits PSC operational lifetime.
• Interface engineering is crucial for improving PSC performance and stability.

Purpose of the Study:

• To investigate the use of TPA-CN organic dye as a self-assembled monolayer (SAM) for interface modification in inverted PSCs.
• To enhance the performance and long-term stability of NiO_x-based inverted PSCs.
• To understand the molecular mechanisms behind interface passivation and charge transfer.

Main Methods:

• Utilized TPA-CN as SAM molecules for interface modification between NiO_x and perovskite layers.
• Characterized the passivating effects of TPA-CN on Ni³⁺ and Pb²⁺ defects.
• Analyzed charge transfer dynamics and device performance metrics (PCE).
• Assessed device stability under prolonged light illumination and ambient conditions.

Main Results:

• TPA-CN SAMs effectively passivated Ni³⁺ defects in NiO_x and undercoordinated Pb²⁺ in perovskite, reducing trap density.
• Enhanced hole extraction and charge transfer from perovskite to NiO_x were observed.
• Achieved a peak power conversion efficiency (PCE) of 25.54% for modified devices, compared to 21.80% for control devices.
• Unencapsulated devices retained 89.2% of initial PCE after 1800 h (ISOS-D-1) and 95.3% after 500 h of 1-sun illumination.

Conclusions:

• TPA-CN serves as an effective molecular bridge, improving both performance and stability of inverted PSCs.
• This molecular design approach offers a viable strategy for developing high-performance, stable perovskite solar cells.
• Interface engineering with SAMs is a promising route for overcoming degradation challenges in PSCs.