Buried Interface Engineering in Perovskite Solar Cells: Selective vs Spontaneous Heterointerface Modulation Using...

Area of Science:

• Materials Science
• Photovoltaics
• Nanotechnology

Background:

• Perovskite solar cells (PSCs) rely on heterointerface modulation due to their multilayered structure, which can create defects.
• Spontaneous heterointerface modulation (SPHM) materials offer a process-free approach to modulate interfaces during PSC fabrication.
• Tetrafluoroborate (BF4-)-based materials are known SPHMs that can enhance PSC performance but may degrade perovskite bulk properties.

Purpose of the Study:

• To develop a new interface modulation strategy that avoids the bulk degradation issues associated with SPHM.
• To investigate the effectiveness of selective heterointerface modulation (SEHM) using BF4-based materials on the perovskite/electron transport layer interface.
• To compare the performance and material compatibility of SEHM versus SPHM.

Main Methods:

• Defined and implemented an ex situ surface treatment (SEHM) on the TiO2 layer prior to perovskite deposition.
• Utilized a BF4-based material for SEHM to modulate the buried perovskite/electron transport material (ETM) interface in n-i-p PSCs.
• Analyzed the impact of SEHM on both the perovskite bulk properties and the heterointerface characteristics.

Main Results:

• SEHM effectively modulated the perovskite/ETM interface with negligible impact on the FAPbI3 perovskite bulk properties.
• SEHM significantly enhanced photovoltaic performance, primarily by increasing the open-circuit voltage, an improvement not achieved by SPHM.
• The SEHM approach demonstrated superior compatibility with BF4-based modulators susceptible to decomposition compared to SPHM.

Conclusions:

• SEHM is a potent and versatile technology for interface modulation in PSCs, especially when using modulators prone to decomposition.
• This technique offers advantages over SPHM by preserving perovskite bulk integrity while effectively enhancing device performance.
• SEHM is broadly applicable beyond BF4-based systems, paving the way for advanced PSC development and materials science innovation.