A collaborative team from École Polytechnique Fédérale de Lausanne (EPFL), the University of Applied Sciences and Arts of Western Switzerland (HES-SO Vaud), and Politecnico di Milano has engineered a highly efficient and stable perovskite solar cell (PSC) using a novel approach combining the chemical additive 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) with rapid infrared annealing (FIRA).
The method leverages TEMPO for bulk passivation and rapid photonic annealing to produce formamidinium lead iodide (FAPI₃)-based PSCs with exceptional performance and stability. By employing FIRA, the researchers fabricated TEMPO-FAPI₃ PSCs achieving power conversion efficiencies (PCEs) exceeding 20%.
The TEMPO additive accelerates crystallization kinetics, yielding films with enhanced uniformity and reduced defect densities. This improvement was confirmed through photoluminescence (PL) spectroscopy, profilometry, and positron annihilation lifetime spectroscopy (PALS).
Stability tests conducted under ISOS protocols revealed that TEMPO-FAPI₃ devices retained over 90% of their initial efficiency after 4,296 hours of operational and thermal stress, demonstrating unprecedented durability for a rapidly processed technology. The additive’s primary effect— passivation of grain boundaries and surface defects—significantly reduced nonradiative recombination rates and defect densities, positioning TEMPO as a promising additive for scalable, durable FAPI₃ PSC fabrication.
This work underscores the potential of combining additive-based passivation with rapid annealing to provide a scalable strategy for manufacturing durable, high-performance PSCs, marking a critical step toward the commercial viability of perovskite-based photovoltaics.
