Multifunctional Engineering-Enabled Electron Transport in SnO₂ for Sn-Based Perovskite Solar Cells in the n-i-p...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• The two-step sequential deposition technique for tin (Sn) perovskite solar cells is effective in the inverted p-i-n configuration.
• This technique fails in the TiO2-based n-i-p configuration due to Sn2+ oxidation in the SnI2 nucleation layer during pore infiltration.
• Ambipolar SnO2, typically used, only facilitates hole transport in Sn perovskite, hindering efficient device operation.

Purpose of the Study:

• To develop a functional n-i-p tin (Sn) perovskite solar cell using a two-step sequential deposition method.
• To address the Sn2+ oxidation issue and improve charge transport at the SnO2/SnI2 interface.
• To enable selective electron transport in the electron transport layer (ETL) for enhanced device performance.

Main Methods:

• Fabrication of Cl-doped SnO2 (Cl:SnO2) with surface functionalization using multifunctional polybenzoxazine (p-Benz).
• Integration of Cl:SnO2 and p-Benz in the n-i-p configuration for Sn perovskite solar cells.
• Characterization of interfacial properties and device performance under illumination.

Main Results:

• Cl:SnO2 with p-Benz functionalization successfully circumvented the interfacial redox reaction, preventing Sn2+ oxidation.
• p-Benz altered photoemissive properties and introduced charge transport resistance, minimizing carrier leakage.
• The modified n-i-p device demonstrated efficient hole injection and internal electric field formation, leading to a functioning planar device.

Conclusions:

• The developed strategy enables the use of the two-step method in the n-i-p configuration for Sn perovskite solar cells.
• Facilitating selective electron transport in Cl:SnO2 is crucial for device functionality.
• This work highlights the versatility in device engineering for Sn perovskite solar cells.