Buried Interface Passivation with "Super-Choline" Glycerophosphocholine for Efficient Regular Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) efficiency is limited by defects at the SnO2/perovskite interface, causing recombination and hindering charge extraction.
• Interface engineering is crucial for improving PSC performance and stability.
• Defects like oxygen vacancies on SnO2 and Pb2+/I- antisites in perovskite are key challenges.

Purpose of the Study:

• To introduce l-α-glycerophosphocholine (GPC) as a bifunctional modifier for the SnO2/perovskite buried interface.
• To investigate the defect passivation and charge transport enhancement mechanisms of GPC.
• To improve the power conversion efficiency (PCE) and stability of PSCs.

Main Methods:

• GPC was used as a modifier at the SnO2/perovskite interface.
• 4-tert-butylpyridine was added to the perovskite precursor to reduce PbI2 secondary phase and improve crystallinity.
• Device performance, including power conversion efficiency (PCE) and open-circuit voltage (Voc), was characterized.
• Device stability was assessed under nitrogen atmosphere aging.

Main Results:

• GPC passivated oxygen vacancies on SnO2 and coordinated with Pb2+/I- defects, forming a molecular bridge.
• The addition of 4-tert-butylpyridine improved perovskite crystallinity.
• Optimized PSCs achieved a champion PCE of 25.31% with a low Voc loss of 0.347 V.
• Unencapsulated devices retained 83% of their initial PCE after 1300 h of aging in N2.

Conclusions:

• GPC acts as an effective bifunctional modifier for the SnO2/perovskite buried interface.
• Interface engineering with GPC significantly enhances charge transport and suppresses recombination.
• The developed PSCs demonstrate high efficiency and improved operational stability, highlighting GPC's potential for future photovoltaic applications.