Engineering of Volatile Cations in Tetrafluoroborate-Based Spontaneous Heterointerface Modulators for Perovskite...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) require defect modulation at heterointerfaces for high efficiency.
• Spontaneous heterointerface modulators (SHMs) enhance PSC fabrication but suffer from concentration sensitivity.

Purpose of the Study:

• To develop a general strategy to mitigate the concentration sensitivity of SHMs.
• To engineer volatile cations in tetrafluoroborate (BF4)-based SHMs for improved PSC performance.

Main Methods:

• Utilizing volatile cations (ammonium, methylammonium, formamidinium) in BF4-based SHMs as additives for formamidinium lead halide (FAPbI3) perovskite photoabsorbers.
• Comparing the effects of different cation volatilities on SHM functionality and PSC performance.
• Analyzing the concentration sensitivity of various BF4-based SHMs.

Main Results:

• All tested BF4-based SHMs, when used in optimal amounts, effectively enhanced PSC photovoltaic performance.
• The tetrafluoroborate (BF4-) anion was identified as crucial for optimal SHM functionality.
• NH4BF4, containing the most volatile cation, exhibited the most moderate concentration sensitivity, validating the proposed strategy.

Conclusions:

• Leveraging the volatility of SHM components offers a viable strategy to address concentration sensitivity issues in SHMs.
• This material design approach can lead to broader implementation of spontaneous heterointerface modulation techniques in PSCs.
• Innovations in SHM design, enabled by this strategy, will promote the development of high-performance perovskite solar cells.