Ionic Liquids Dramatically Boost Stability of Next-Generation Perovskite Solar Cells
Table of Contents
A new strategy employing carefully engineered ionic liquids promises to overcome a key hurdle in the development of affordable and efficient perovskite solar cells – their long-term stability. Researchers have demonstrated that these novel additives allow perovskite cells to retain 90% of their initial performance for over 1,500 hours under harsh conditions, paving the way for wider adoption of this promising solar technology.
Perovskite solar cells have emerged as a compelling alternative to traditional silicon-based cells due to their potential for high power conversion efficiencies and lower manufacturing costs. However, a significant drawback has been their susceptibility to degradation over time, limiting their practical application. A team from Purdue University, Emory University, and other institutes has now published findings in Nature Energy detailing a breakthrough in addressing this challenge.
The Promise of Perovskites and the Stability Problem
Solar cells convert sunlight into electricity, and are crucial in the global shift away from fossil fuels. While silicon has long been the dominant material in solar cell production, researchers are actively exploring alternatives. Perovskites, particularly halide perovskites, have garnered significant attention. These materials, characterized by a specific crystal structure (ABX₃) containing halides, excel at absorbing light and transporting electrical charge, leading to high power conversion efficiencies (PCEs).
Despite these advantages, most halide perovskite solar cells degrade more rapidly than their silicon counterparts. This instability stems from imperfections, or defects, within the perovskite material itself. “It is very important to minimize the defects in the perovskite layer, as well as the two interfaces,” explained a senior researcher involved in the study. “Despite widespread efforts aimed at improving the top interface, few efforts have been made for bulk defect passivation and bottom interface.”
Engineering Stability with Ionic Liquids
The research team’s innovative approach centers on the use of ionic liquids – salts that remain liquid at low temperatures and exhibit strong interactions with other materials. Inspired by earlier work in the field, they embarked on a mission to design new ionic liquid molecules specifically tailored to interact with perovskites and mitigate degradation.
“Our group is specialized in organic synthesis, hybrid perovskite crystal growth, and device engineering,” stated a lead author of the paper. “Our industry sponsor asked us to synthesize novel additives to improve the long-term stability of the devices. We noticed previous studies used simple, commercially available ionic liquids without carefully engineering the molecule structures.”
The team’s newly designed ionic liquids proved significantly more effective than those used in prior research. The most promising compound, dubbed MEM-MIM-CI, binds strongly to positively charged lead ions within the perovskite structure and fills halide vacancies – essentially patching up defects that contribute to instability.
How MEM-MIM-CI Works at the Interface
The researchers discovered that the addition of these ionic liquids alters the crystallization process of the perovskite material. “These new ionic liquids, when added into the perovskite precursor, introduce an intermediate phase during the crystallization process,” explained a researcher. “This intermediate phase slows down the crystallization and promotes the growth of large grain-sized perovskite with fewer defects.”
Crucially, the ionic liquid preferentially accumulates at the bottom interface of the perovskite layer, further suppressing defect formation. This targeted approach addresses a previously overlooked area of instability. An illustration detailing the effect of the ionic liquid on the buried perovskite interface is available in the Nature Energy publication (DOI: 10.1038/s41560-025-01906-6).
Rigorous Testing Under Harsh Conditions
To assess the effectiveness of their approach, the team subjected the enhanced solar cells to rigorous testing. Initially, they evaluated performance at temperatures between 65–80°C under full sunlight (1-Sun irradiation). When a sponsor requested even more demanding conditions, the researchers pushed the limits further.
“Our sponsor wanted to see how the device degraded under even harsher conditions, at least 90°C with light,” said Dr. Wenzhan Xu, first author of the paper. “We demonstrated that our devices retain 90% of their initial performance for over 1,500 hours under continuous 1-Sun illumination and temperatures of 90°C under open circuit condition—this is harsher than the condition typically used by other researchers.”
Towards Commercialization and Widespread Adoption
These results highlight the significant potential of carefully designed ionic liquids to enhance the stability of perovskite solar cells. The materials used are readily synthesized and scalable, making them suitable for industrial production. “This strategy has the potential to be extended to the industrial fabrication of large-area PSC devices because the ionic liquids used are also compatible with scalable, solution-based deposition techniques such as blade coating,” a researcher noted.
Furthermore, the team found that the ionic liquids can improve both the efficiency and stability of wide-bandgap and lead-free perovskite systems, expanding their applicability to tandem solar cell configurations. The researchers are now focused on designing even more effective molecules and gaining a deeper understanding of the fundamental interactions between ionic liquids and perovskites using advanced spectroscopic and imaging techniques.
“We welcome collaborations with other industry partners (the patent related to this technology is available for licensing),” a researcher stated. “We hope that this innovation will drive the commercialization and widespread adoption of stable PSCs.”
More information: Wenzhan Xu et al, Ionic liquids improve the long-term stability of perovskite solar cells, Nature Energy (2025). DOI: 10.1038/s41560-025-01906-6.
© 2025 Science X Network
Citation: Ionic liquids slow perovskite degradation: Solar cells retain 90% performance at 90°C (2025, December 21) retrieved 21 December 2025 from https://techxplore.com/news/2025-12-ionic-liquids-perovskite-degradation-solar.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
