Modified near-infrared annealing enabled rapid and homogeneous crystallization of perovskite films for efficient solar modules

A landmark report in Nano-Micro Letters demonstrates how a modified near-infrared annealing (NIRA) process—coupled with precise excess-PbI₂ compositional engineering—turns blade-coated perovskite films into record-performing, large-area solar modules in only 20 s. Led by Jing Li from Xiamen University, the work shatters the energy-throughput bottleneck that has hindered industrial-scale perovskite photovoltaics.

Why This Research Matters

• Defeating the Annealing Bottleneck: Conventional hot-plate annealing (HPA) demands > 10 min at > 100 °C, consuming excessive energy and creating non-uniform crystallization across > 100 cm² modules. NIRA slashes processing time by 30 × and halves energy use while delivering superior film quality.

• Enabling Commercial-Scale Efficiency: Blade-coated 36 cm² and 100 cm² modules reach certified PCEs of 22.03 % and 20.18 %, respectively—among the highest reported for fully scalable perovskite devices—and retain ≥ 90 % output after 1000 h ISOS-L-1 and 85 °C/85 % RH stress tests.

Innovative Design and Mechanisms

• Triple-Mode Heat Transfer: A semi-closed NIRA chamber couples radiation, conduction and convection, reaching 300 °C surface temperature in 20 s with < 5 °C lateral gradients, ensuring uniform energy delivery across 100 cm² substrates.

• PbI₂-Seeded Nucleation & Passivation: 10 % excess PbI₂ acts as nucleation sites during vacuum-flash desolvation, suppressing pinholes and enabling rapid Ostwald ripening. Post-anneal, an ultrathin PbI₂ layer (≤ 2 nm) simultaneously passivates surface defects and tunes interfacial energetics, cutting trap density from 1.15 × 10¹⁶ to 8.4 × 10¹⁵ cm^-3.

Applications and Future Outlook

• Scalable Manufacturing: Fully automated blade coating, laser scribing (95.6 % geometric fill factor) and roll-to-roll-compatible NIRA hardware demonstrate a clear path to gigawatt-scale production lines.

• Universal Process Window: The strategy is compatible with FA/Cs mixed-cation perovskites and can be integrated with SnO₂/ZnTiO₃ electron-transport stacks, opening doors for tandem silicon/perovskite modules targeting > 30 % PCE.

• Next Steps: The team will extend NIRA to flexible foils, slot-die coating and perovskite/silicon tandem architectures while incorporating additional surface passivation chemistries to push module PCE beyond 25 %.

Conclusions
By marrying rapid near-infrared energy delivery with PbI₂-mediated nucleation control, this work establishes a universal, energy-efficient route to high-quality, large-area perovskite films. The 20-second NIRA process not only unlocks industrial throughput but also sets a new performance benchmark for next-generation photovoltaic modules poised for mass deployment.