Spacer Engineering Using Aromatic Formamidinium in 2D/3D Hybrid Perovskites for Highly Efficient Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Chemistry

Background:

• 2D/3D hybrid perovskites offer a promising route to combine the stability of 2D structures with the high efficiency of 3D perovskites.
• Organic spacers are crucial components in these hybrid materials, influencing their structural and electronic properties.

Purpose of the Study:

• To develop and investigate a new class of aromatic formamidinium (ArFA) spacers for 2D/3D perovskite solar cells.
• To understand the structure-property relationships and the impact of ArFA spacers on device performance and stability.

Main Methods:

• Synthesis and characterization of aromatic formamidinium (ArFA) compounds.
• Fabrication and testing of 2D/3D perovskite solar cells utilizing ArFA spacers.
• Analysis of crystalline growth, defect states, and carrier dynamics using advanced characterization techniques.

Main Results:

• The bulky ArFA spacers promote enhanced crystalline growth and orientation in 2D/3D perovskites.
• Multiple NH···I hydrogen-bonding interactions between ArFA and inorganic layers reduce defect states and increase carrier lifetime.
• A benzamidine hydrochloride (PhFACl)-based device achieved a certified efficiency of 23.36%, significantly outperforming the control device (19.02%).
• The optimized device demonstrated improved long-term thermal stability, maintaining performance after 1400 hours at 80 °C.

Conclusions:

• Aromatic formamidinium (ArFA) spacers are effective in optimizing the performance of 2D/3D perovskite solar cells.
• The developed ArFA spacers offer a viable strategy for achieving highly efficient and stable perovskite solar cells.
• This work highlights the potential of tailored organic spacers for advancing perovskite photovoltaic technology.