Innovative Self-Assembled Bilayer Film Enhances Thermal Resilience of Perovskite Solar Cells
perovskite solar cells” title=”Schematic diagram illustrating the structure of the self-assembled bilayer (SAB). Credit: Nature Energy (2025). DOI: 10.1038/s41560-024-01689-2″ width=”800″ height=”530″/>
In recent years, solar energy technologies have gained momentum, playing a vital role in mitigating greenhouse gas emissions. Although silicon remains the dominant material in today’s solar cells, researchers are exploring alternative substances that show promise for advancing photovoltaic solutions.
The Promise and Challenges of Perovskite Solar Cells
Among these alternatives, perovskites stand out due to their potential for creating more cost-effective solar cells with impressive power conversion efficiencies. However, one significant drawback is their relative instability compared to traditional silicon solar cells; high temperatures and variable environmental conditions often hinder performance.
A common factor contributing to the degradation of these devices is their dependence on hole-selective self-assembled monolayers (SAMs), which are molecular films designed to attract positive charge carriers. Unfortunately, these SAMs sometimes fail to bond effectively with cell surfaces, resulting in increased thermal instability within PSCs.
A Breakthrough in Material Design
Researchers from Xi’an Jiaotong University and Uppsala University have recently introduced a novel self-assembled bilayer film aimed at addressing the shortcomings associated with standard SAMs. Their findings were detailed in a publication within *Nature Energy*, showcasing how this innovative bi-layer molecular film can better adhere to PSCs while significantly boosting thermal stability as well as overall efficiency.
“To ensure practical application of PSC technology, enhanced stability against elevated temperatures and temperature fluctuations is crucial,” emphasized Bitao Dong, Mingyang Wei, along with their research team.
Covalent Bonding for Enhanced Stability
The newly developed bilayer technology introduces an additional upper layer comprised of triphenylamine onto conventional phosphonic acid-based SAM structures. This upper layer forms covalent bonds with the underlying SAM substance creating a robust polymer network.
“This polymerized network generated through Friedel–Crafts alkylation demonstrated resilience against thermal degradation at temperatures reaching up to 100°C over extended periods,” Dong and his colleagues reported. “Additionally, this approach resulted in improved adhesive properties when interfaced with perovskites—achieving an adhesion energy increase by approximately 70% over conventional methods.”
Promising Benefits across Applications
The research team conducted multiple evaluations that indicated superior adhesion strength between their inventive bilayers and perovskite surfaces compared to commonly used mono-layer SAM options. Furthermore, this versatile production method can adapt easily for various types of SAM-forming compounds.
Tests were also performed using inverted PSC designs incorporating this new self–assembling film which yielded encouraging results—demonstrating high power conversion efficiencies while minimizing reduction rates over time alongside improvements in high-temperature durability.
“We observed power conversion efficiencies surpassing 26% among our tested inverted PSC models,” stated Dong and colleagues proudly reporting metrics below only 4% efficiency loss after exposure exceeding two thousand hours under damp heat conditions (85°C at 85% humidity) as well as a mere loss realm under three percent during extensive cycling tests simulating extreme temperature variations ranging from -40°C up through +85°C.” These findings align impressively within recognized benchmarks set forth by International Electrotechnical Commission standards DOC20161:2021 regarding temperature resilience criteria.”
// Future Implications
Toward Advanced Photovoltaic Solutions
This emerging methodology holds great promise not only for enhancing existing PV technologies but also for catalyzing further innovations across diverse realms spanning beyond just affordable renewable energy generation methods altogether leveraging significant upgrades bolstering long-term sustainability efforts globally moving forward into tomorrow’s clean-tech aspirations!
more information:
Bitao Dong et al., *Self-organized Bilayers Enabling Superior Thermal Resistance Characteristics In Perovskitic Solar Cells*, *Nature Energy* (2025). DOI: 10.1038/s41560–024–01689–02.
