Innovative Coating Boosts Stability of Perovskite Solar Cells

Recent advancements in perovskite solar cell technology have marked a significant breakthrough in the quest for energy-efficient solutions. An international research team, led by Prof. Dr. Antonio Abate, has developed a novel coating technique that enhances the stability and efficiency of these solar cells, which are already known for their low production costs and high power output.

The new approach applies a fluorinated barrier compound at the interface of the perovskite layer and the top contact layer, dramatically increasing stability while pushing efficiency levels to nearly 27%. Remarkably, after 1,200 hours of continuous operation under standard illumination, the cells demonstrated no efficiency loss, a significant improvement over current silicon-based alternatives.

Research Collaboration and Findings

The study, published in Nature Photonics, involved collaborative efforts from research teams in China, Italy, Switzerland, and Germany. The innovative technique utilizes a fluorinated compound that forms a nearly compact monomolecular film, facilitating a sliding action between the perovskite and the buckyball (C60) contact layer. This configuration minimizes defects and energy losses, leading to better overall performance.

“We used a fluorinated compound that can slide between the perovskite and the buckyball contact layer, forming an almost compact monomolecular film,” explains Abate. This “Teflon-like” layer not only isolates the perovskite from the contact layer but also significantly enhances the structural integrity of both layers, with a particular emphasis on the C60 layer’s uniformity and compactness.

The primary experimental research was conducted by Guixiang Li, the first author of the study, while he was a Ph.D. student in Abate’s team. Li, who is currently a professor at Southeast University in Nanjing, China, continues to engage in this collaborative research.

Enhanced Performance Metrics

The introduction of this intermediate layer has proven to boost lab-scale efficiency to 27%, surpassing the previous benchmark of 26% achieved without the barrier. The stability improvements are noteworthy; while cells without the Teflon-like layer experienced a 20% efficiency drop after just 300 hours, the newly developed cells maintained their efficiency after the equivalent of one year of outdoor use.

In addition to efficiency, the coating provides remarkable thermal stability. The solar cells exhibited resilience after being aged for 1,800 hours at 85 °C and tested across 200 cycles between –40 °C and +85 °C. The perovskite solar cells are designed with an inverted (p-i-n) structure, making them particularly suitable for integration into tandem solar cells alongside silicon technologies.

The concept of utilizing Teflon-like molecules to create an intermediate film has been a long-standing idea for Abate. “The thought has been in my mind since my postdoctoral days in Henry Snaith’s lab, where groundbreaking research on perovskite materials began. Back in 2014, we were only achieving 15% efficiency, which declined significantly within a matter of hours. The progress we have made is substantial,” he reflects.

These advancements pave the way for the next generation of highly efficient and stable perovskite-based optoelectronic devices, potentially transforming the solar energy landscape. With ongoing research and collaboration among international teams, the future of solar technology appears brighter than ever.