Stabilizing perovskite fabrication in ambient air

Abstract

Perovskite-based solar cells have advanced rapidly because of their high efficiency potential, low-cost processing, and flexible fabrication routes. While silicon solar cells remain the dominant commercial technology, combining perovskites with silicon in tandem architectures offers a clear pathway to exceed the efficiency limits of single-junction devices. By pairing perovskite’s tunable absorption with silicon’s proven performance, perovskite–silicon tandem solar cells open new opportunities for high-efficiency photovoltaics. Yet translating these advances from laboratory demonstrations to scalable manufacturing remains a major challenge. A central obstacle lies in fabricating high-quality perovskite films under ambient conditions. Moisture in air directly interferes with perovskite crystallization, leading to disordered crystal growth, surface degradation, and the accumulation of non-ideal secondary phases. Although thermal annealing is often used to improve crystallinity, the combined effects of heat and humidity can instead accelerate irreversible degradation when processing in air. Together, these factors make crystallization control under ambient conditions particularly difficult, underscoring the need for new strategies that can stabilize film formation without relying on tightly controlled environments. Previous studies have explored several approaches to optimize perovskite film fabrication in ambient air. Strategies such as solvent engineering and longitudinal homogeneous intermediates in hybrid sequential deposition have been developed to address moisture-related issues and enhance film uniformity. Additionally, techniques like the P1.5 process, which introduces a diffusion barrier layer, have been used to improve film stability by reducing moisture and oxygen intrusion. However, challenges persist, particularly in achieving the same performance as films fabricated in controlled environments. While various composition and additive engineering techniques have been explored, integrating these methods with certain deposition techniques and fully mitigating the impact of moisture remains difficult. The need for more effective strategies, specifically tailored to control crystallization under ambient conditions, is evident, highlighting the gap in existing methods for scalable, high-performance perovskite-based solar cells. Now, writing in Joule, Tan et al. tackle this challenge with a novel approach that intervenes in the wet-film stage to stabilize the crystallization process. Instead of relying on environmental controls to eliminate moisture, the authors introduce an additive, n-butylammonium thiocyanate (nBASCN), to regulate crystallization dynamics. Implemented as part of the hybrid sequential deposition process, this wet-film intervention modifies the crystallization pathway, preventing premature nucleation and promoting uniform growth. The perovskite film evolves differently with and without nBASCN intervention, demonstrating how the additive stabilizes the fabrication process in ambient air.

1. Introduction

Perovskite-based solar cells have advanced rapidly because of their high efficiency potential, low-cost processing, and flexible fabrication routes. While silicon solar cells remain the dominant commercial technology, combining perovskites with silicon in tandem architectures offers a clear pathway to exceed the efficiency limits of single-junction devices. By pairing perovskite’s tunable absorption with silicon’s proven performance, perovskite–silicon tandem solar cells open new opportunities for high-efficiency photovoltaics. Yet translating these advances from laboratory demonstrations to scalable manufacturing remains a major challenge.

A central obstacle lies in fabricating high-quality perovskite films under ambient conditions. Moisture in air directly interferes with perovskite crystallization, leading to disordered crystal growth, surface degradation, and the accumulation of non-ideal secondary phases. Although thermal annealing is often used to improve crystallinity, the combined effects of heat and humidity can instead accelerate irreversible degradation when processing in air. Together, these factors make crystallization control under ambient conditions particularly difficult, underscoring the need for new strategies that can stabilize film formation without relying on tightly controlled environments.

Previous studies have explored several approaches to optimize perovskite film fabrication in ambient air. Strategies such as solvent engineering and longitudinal homogeneous intermediates in hybrid sequential deposition have been developed to address moisture-related issues and enhance film uniformity. Additionally, techniques like the P1.5 process, which introduces a diffusion barrier layer, have been used to improve film stability by reducing moisture and oxygen intrusion. However, challenges persist, particularly in achieving the same performance as films fabricated in controlled environments. While various composition and additive engineering techniques have been explored, integrating these methods with certain deposition techniques and fully mitigating the impact of moisture remains difficult. The need for more effective strategies, specifically tailored to control crystallization under ambient conditions, is evident, highlighting the gap in existing methods for scalable, high-performance perovskite-based solar cells.