Italian scientists build large-area perovskite solar modules based on nickel oxide with 12.6% efficiency – pv magazine International

September 24, 2024 Emiliano Bellini

Researchers University of Rome Tor Vergata 15 cm x 15 cm inverse perovskite solar modules based on a hole transport layer (HTL) made of inorganic nickel oxide (NiOx) have been developed in Italy.

“Our research stands out for optimizing the nickel oxide deposition over a large area using the blade coater, a scalable technique that is fundamental to reduce the technological gap between basic research and commercialization,” said Luigi Angelo Castriotta, lead author of the study. pv magazine“This technique is optimized to be performed under standard ambient conditions of 25% average humidity, eliminating the need for controlled environments such as nitrogen often used in traditional production methods.”

In inverse perovskite solar cells and modules, the perovskite cell material is deposited onto the HTL and then covered with an electron transport layer (ETL) – the exact opposite of traditional device architecture. Inverse perovskite solar devices generally exhibit strong stability, but have lagged behind traditional devices in terms of conversion efficiency and cell performance.

Scientists explained that inverse perovskite cells generally use a cell based on HTL. poly(triarylamine) (PTAA), they said, is known for its high performance in printable devices. They chose NiOx because of the similar efficiency levels compared to PTAA, as well as the improved long-term stability offered by this material. “Unlike PTAA, NiO_X “Due to its inorganic structure, it is potentially low cost, extremely photostable, chemically stable, has excellent optical transmittance and is hydrophilic,” they explained.

However, they warned that integrating NiO is also important._X HTL at ambient conditions using printable methods results in lower efficiency compared to PTAA-based devices. To solve this problem, they decided to print NiO_X The cell is coated with a doctor blade, a method typically used to create films of well-defined thicknesses without any spin-coating steps.

“We cut nickel(II) chloride (NiCl) with a doctor blade₂·6S₂“The films were then annealed at 300 C to promote decomposition and oxidation, utilizing atmospheric oxygen to form NiO_X film.”

The solar panel is built with NiO, an ITO substrate_X HTL, a self-assembled monolayer (SAM) consisting of (2-(3,6-Dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid (MeO-2PACz), a perovskite absorber, an ETL based on buckminsterfullerene (C60), A bathocuproine (BCP) buffer layer and a copper (Cu) metal contact.

The first four layers were produced by the doctor blade method under ambient conditions, while the remaining were bonded via thermal evaporation.

“We found that adding SAM between the nickel oxide and the perovskite significantly improves the morphology and uniformity of the perovskite film, reduces defects such as pinholes, and increases the stability of the device over time,” Castriotta explains.

Tested under standard lighting conditions, the 110 cm² perovskite panel achieved 12.6% power conversion efficiency, 19.67 mA/cm2 short-circuit current density, and 63.49% fill factor. The device also retained 84% of its initial efficiency after a 1000-hour thermal stress test at 85°C in air.

“These results highlight the potential of NiO_X “Opening new avenues for large-scale, cost-effective production of PSCs and perovskite solar modules,” the academics wrote. “Future research should focus on further optimizing the fabrication process and exploring the commercial viability of these technologies.”

New approach presented in “study”Stable and sustainable perovskite solar modules by optimizing fin-coating nickel oxide deposition over a 15 cm × 15 cm area” It was published communication materials.

“Our research not only addresses one of the major hurdles to commercialization of perovskite solar cells—the scalability of the manufacturing process—but also does so with a sustainable approach that avoids the use of toxic solvents and complex manufacturing environments,” Castriotta said. ““The result is a promising technology that could accelerate the industrial-scale adoption of perovskite solar cells while maintaining high efficiency and long-term stability.”