# Ammonia Borane All-In-One Modification Strategy Enables High-Performance Perovskite Solar Cells

## TL;DR

A new strategy using ammonia borane improves perovskite solar cells by fixing defects and boosting efficiency and stability.

## Contribution

A multifunctional all-in-one modification strategy using ammonia borane for dual interfacial treatment in perovskite solar cells.

## Key findings

- The strategy achieves a champion efficiency of 26.43% with minimal hysteresis.
- Devices show 90% PCE retention after 500 hours under continuous illumination.
- Eliminates the need for separate interface treatments, simplifying fabrication.

## Abstract

An all-in-one modification strategy was developed by introducing a multifunctional complex ammonia borane (BNH6) into the buried and upper interfaces simultaneously.BNH6 uniquely realizes dual-interfacial defect passivation and iodide oxidation suppression by interacting with SnO2 through hydrolysis, coordinating with Pb2+ and inhibiting the oxidation of I−.The optimized perovskite solar cells achieve a champion efficiency of 26.43% (certified, 25.98%) with negligible current density–voltage hysteresis and significantly improved thermal and light stability.

An all-in-one modification strategy was developed by introducing a multifunctional complex ammonia borane (BNH6) into the buried and upper interfaces simultaneously.

BNH6 uniquely realizes dual-interfacial defect passivation and iodide oxidation suppression by interacting with SnO2 through hydrolysis, coordinating with Pb2+ and inhibiting the oxidation of I−.

The optimized perovskite solar cells achieve a champion efficiency of 26.43% (certified, 25.98%) with negligible current density–voltage hysteresis and significantly improved thermal and light stability.

The online version contains supplementary material available at 10.1007/s40820-025-01951-6.

Perovskite solar cells have achieved remarkable progress in photovoltaic efficiency. However, interfacial defects at the buried and upper interfaces of perovskite layer remain a critical challenge, leading to charge recombination, ion migration, and iodine oxidation. To address this, we propose a novel all-in-one modification strategy employing ammonia borane (BNH6) as a multifunctional complex. By incorporating BNH6 at both buried and upper interfaces simultaneously, we achieve dual-interfacial defect passivation and iodide oxidation suppression through three key mechanisms: (1) hydrolysis-induced interaction with SnO2, (2) coordination with Pb2+, and (3) inhibition of I− oxidation. This approach significantly enhances device performance, yielding a champion power conversion efficiency (PCE) of 26.43% (certified 25.98%). Furthermore, the unencapsulated device demonstrates prominent enhanced operation stability, maintaining 90% of its initial PCE after 500 h under continuous illumination. Notably, our strategy eliminates the need for separate interface treatments, streamlining fabrication and offering a scalable route toward high-performance perovskite photovoltaics.

The online version contains supplementary material available at 10.1007/s40820-025-01951-6.