Reproducible fabrication of perovskite photovoltaics via supramolecule confinement growth

As the demand for high-efficiency solar energy continues to rise, the challenge of reproducibly fabricating high-quality perovskite films remains a major bottleneck. Now, researchers from East China University of Science and Technology, led by Professor Shuang Yang and Professor Yu Hou, have presented a breakthrough strategy using supramolecule-confined growth to achieve ultraflat, electronically homogeneous perovskite films. This work offers a transformative approach to enhance the reproducibility and performance of perovskite solar cells.

Why Supramolecule Confinement Matters

• Reproducibility: The supramolecule capping layer significantly reduces device-to-device and batch-to-batch performance variations, a long-standing issue in perovskite photovoltaics.
• Surface Quality: Enables the formation of ultrasmooth perovskite films with RMS roughness <10 nm, enhancing interfacial contact and device performance.
• Crystallization Control: Host–guest interactions between calixarene and solvent molecules regulate desolvation kinetics, leading to uniform nucleation and growth.

Innovative Design and Features

• Capping Layer Engineering: A calixarene-based supramolecular layer (tBTCA) is introduced atop the perovskite precursor film to confine crystal growth and modulate solvent evaporation.
• Host–Guest Chemistry: The calixarene layer captures DMSO molecules via host–guest interactions, slowing desolvation and enabling controlled crystallization.
• Interface Initiation: Perovskite formation begins at the molecule–precursor interface, not the bulk or bottom layer, ensuring uniform grain growth and surface flatness.

Applications and Future Outlook

• Photovoltaic Efficiency: Solar cells fabricated using this method achieved a champion power conversion efficiency (PCE) of 25.09%, with significantly reduced performance variation.
• Universal Applicability: The strategy is effective across various perovskite compositions, including FA_0.8MA_0.2Pb(I_0.8Br_0.2)₃ and Cs_0.05FA_0.81MA_0.14PbI_2.85Br_0.15.
• Stability and Reproducibility: Devices show enhanced long-term stability and narrow PCE distributions, with standard deviations dropping from 0.64% to 0.26%.

Challenges and Opportunities

The study highlights the importance of interfacial engineering in perovskite film formation. Future research will focus on expanding the library of supramolecular capping agents and optimizing their integration into scalable manufacturing processes.

This comprehensive study provides a materials-level solution to the reproducibility challenge in perovskite solar cells, offering a scalable, low-cost, and high-performance pathway for next-generation photovoltaics. Stay tuned for more groundbreaking work from Professor Shuang Yang and Professor Yu Hou at ECUST!