Chinese Researchers Develop Stable Methylammonium-Free Perovskite Solar Modules
New additive strategy improves efficiency and thermal stability for large-scale solar manufacturing.
1Overcoming Perovskite Thermal Instability
Researchers from the Chinese Academy of Sciences and Dalian Jiaotong University have successfully fabricated methylammonium-free perovskite solar modules. Methylammonium molecules are known for their intrinsic thermal and chemical instability, which often leads to device degradation. By removing these molecules, the team aims to enhance the long-term durability of photovoltaic devices under heat.
2Advanced Slot-Die Coating Technique
The team utilized slot-die coating to manufacture these modules under ambient conditions. This technique is highly valued for its potential in large-scale roll-to-roll production processes. Unlike traditional spin coating, this method allows for the controlled deposition of precursor inks over large substrates, significantly reducing material waste while maintaining uniform thin film formation.
3Synergistic Additive Strategy Employed
To manage crystallization, the researchers implemented a combined additive strategy using rubidium thiocyanate and formamidinium thiocyanate. These additives work through an in situ coordination mechanism to facilitate the conversion of non-photoactive phases into the desired photoactive alpha-phase. This process effectively lowers the energy barrier, ensuring a more stable and efficient crystal structure.
4Expanding the Processing Window
The dual-additive approach significantly widens the processing window for film deposition and annealing to over 100 seconds. By making the crystallization process more tolerant to variability, the researchers achieved dense films with large crystal grains. This improvement reduces residual stress and ensures a uniform vertical compositional gradient across the large-area solar modules.
5Efficiency and Performance Metrics
The developed 54.80 cm² solar module achieved a power conversion efficiency of 22.70 percent. This marks a substantial improvement compared to the 15.8 percent efficiency recorded for reference modules produced without the additive strategy. Furthermore, small-area solar cells fabricated using this method reached a peak efficiency of 26.16 percent during laboratory testing.
6Enhanced Operational Stability Results
Operational stability tests demonstrated the robustness of the new design. Unencapsulated devices maintained 97.76 percent of their initial efficiency after 1,300 hours of continuous operation at 65 degrees Celsius. In contrast, reference devices tested under identical conditions retained only 65.86 percent of their original efficiency, highlighting the success of the additive strategy.
7Scaling Ambient Manufacturing Processes
Achieving homogeneous film coverage remains a primary challenge when transitioning from laboratory-scale devices to larger modules. This research addresses the issue by optimizing the crystallization environment rather than imposing tighter process controls. The findings suggest that ambient-fabricated perovskite photovoltaics can reach high performance levels while remaining compatible with industrial manufacturing requirements.
8Implications for Solar Energy
The study, published in Advanced Materials, provides a scalable pathway for producing stable perovskite solar technology. By eliminating volatile methylammonium and improving crystallization, the researchers have moved closer to commercial viability. Future developments will likely focus on further scaling these modules while maintaining the high efficiency and thermal stability demonstrated here.