A Multifunctional Fluorinated Polymer Enabling Efficient MAPbI3-Based Inverted Perovskite Solar Cells | JoVE Visualize

Area of Science:

Materials Science
Renewable Energy
Photovoltaics

Background:

Polymeric hole-transporting materials (HTMs) are crucial for minimizing defects in perovskite solar cells (PSCs).
Existing HTMs are primarily used in n-i-p PSCs, with limited options for p-i-n inverted architectures.
Current passivation strategies often focus on Pb²⁺ defects, neglecting the detrimental impact of MA⁺ cation defects on device performance and stability.

Purpose of the Study:

To develop a novel polymeric HTM capable of simultaneously passivating both Pb²⁺ and MA⁺ defects in p-i-n inverted perovskite solar cells.
To enhance the efficiency and long-term operational stability of perovskite solar cells through improved defect management.
To explore a new nonfused polymer, BN-12, synthesized via mild polymerization for advanced PSC applications.

Main Methods:

A new nonfused polymer, BN-12, was synthesized using mild polymerization.
The polymer BN-12 was incorporated into p-i-n inverted perovskite solar cells (PSCs) using MAPbI₃ as the absorber layer.
The performance and stability of devices fabricated with BN-12 were compared against those using the commercial HTM PTAA.

Main Results:

The polymer BN-12 demonstrated excellent thermal stability and perovskite precursor wettability due to its aromatic bridge structure.
Chemical anchor sites (C═O and F) in BN-12 effectively controlled perovskite crystallization and suppressed MA⁺ ion migration.
Devices with dopant-free BN-12 achieved a fill factor (FF) of 82.9% and a power conversion efficiency (PCE) of 20.28%, surpassing PTAA-based devices (FF=81.7%, PCE=19.51%).
Unencapsulated BN-12 devices maintained 95% of their initial efficiency after 85 days, significantly outperforming PTAA devices which retained only 50% after 45 days.

Conclusions:

The developed polymer BN-12 offers a promising solution for simultaneously passivating critical defects in p-i-n inverted perovskite solar cells.
BN-12 significantly enhances both the power conversion efficiency and the long-term stability of perovskite devices.
This work provides a new avenue for designing advanced HTMs for stable and efficient perovskite solar cell technologies.