Passivating SnO2/Perovskite Interface: FA+/Oxalate Dual Action

• New research strategy to modify Tin dioxide (SnO2)/perovskite interface by passivating buried defects and modulating carrier dynamics achieves record-breaking power conversion efficiency of 25.05%. Improved energy level alignment and superior interface contacts offer enhanced stability.

Researchers from universities located in China and Korea have developed a new strategy to modify the Tin dioxide (SnO2)/perovskite buried interface by passivating the buried defects in perovskite and modulating carrier dynamics via incorporating formamidine oxalate (FOA) in SnO2 nanoparticles. This strategy utilizes the FA+ cations and oxalate anions to suppress oxygen vacancies and tin interstitial defects on the SnO2 surface and FA+/Pb2+ associated defects at the perovskite buried interface. The modified SnO2 exhibited higher Fermi level, which improves energy level alignment between perovskite and SnO2-FOA and avoids carrier accumulation. Additionally, the FOA could modulate crystal growth of upper perovskite films, leading to high-quality films with minimized grain boundaries and superior interface contacts. The result was a record power conversion efficiency of 25.05% and enhanced stability under light, heat, and moisture conditions.

How Can FOA Improve SnO2/Perovskite Interface?

• FOA can passivate oxygen vacancies and tin interstitial defects on the SnO2 surface, leading to higher Fermi level
• FOA/Pb2+ associated defects at the perovskite buried interface are suppressed, avoiding carrier accumulation
• FOA can modulate crystal growth of upper perovskite films, creating high-quality films with minimized grain boundaries and superior interface contacts
• The use of FOA increased the power conversion efficiency to a record 25.05%, as well as increased stability in light, heat, and moisture conditions