Regulating the Film Growth and Reducing the Defects for Efficient CsPbIBr₂ Solar Cells

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photovoltaics

Background:

• Inorganic lead halide perovskites like CsPbIBr2 are promising for tandem solar cells due to their stability and band gap.
• Improving film quality and reducing defects are key to boosting CsPbIBr2 solar cell efficiency.

Purpose of the Study:

• To investigate the effect of formamidinium acetate (FAAc) on the crystallization dynamics of CsPbIBr2 films.
• To enhance the performance and stability of CsPbIBr2 solar cells through improved film quality.

Main Methods:

• Introducing volatile formamidinium acetate (FAAc) into the CsPbIBr2 precursor solution.
• Analyzing crystallization kinetics, film morphology, defect concentration, and device performance.

Main Results:

• FAAc addition slowed CsPbIBr2 crystallization, yielding pinhole-free films with large grains and smooth surfaces.
• Defect concentration was reduced, and nonradiative recombination was significantly inhibited.
• The champion CsPbIBr2 solar cell achieved a 9.44% power conversion efficiency with improved stability.

Conclusions:

• FAAc is an effective additive for improving CsPbIBr2 film quality and solar cell performance.
• This strategy offers a pathway to reduce defects and suppress recombination in perovskite solar cells.
• Enhanced film quality leads to higher power conversion efficiency and better operational stability.