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Researchers from the US and South Korea have developed a method to make high-quality perovskite films at room temperature. The film was tested on a conventional perovskite solar cell architecture and the result was a power conversion efficiency of over 24%.
An international research team has developed a method to fabricate high-quality perovskite films at room temperature for perovskite solar cell applications. The novel process avoids thermal annealing and additional post-treatments.
The team selected a perovskite composition known as (Csx(FA0.92MA0.08)1-xPb(I0.92Br0.08)3), which was converted to a-FAPbI3 at room temperature. Further conversion was promoted with the addition of an organic linker known as oleylamine or simply OAm. The effect of the method on quality growth patterns was confirmed by in situ X-ray monitoring.
Additionally, to demonstrate the viability of the process on non-traditional photovoltaic substrates and materials, the researchers deposited their perovskite film on a plant leaf, something that would have been impossible with conventional methods.
“The most complicated aspects of the work were understanding the mechanism of operation and demonstrating that the process was gentle enough to deposit perovskite films on fresh sheets, which are very soft and fragile,” the lead author of the research explained to pv magazine. , Thuc-Quyen Nguyen.
The researchers described the fabrication of cells with a planar pin structure to investigate the effect of cesium (Cs) and OAm on performance and stated that they only used printable materials. The fabricated devices had an indium tin oxide substrate with a layer of MeO-2PACz, also known as [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid.
The perovskite adsorbent was then subjected to a two-step spin-coating process and connected to an electron transport layer (ETL) based on phenyl-C61-butyric acid methyl ester ( PCBM) which was also based on spin coating and a baticuproin (BCP) buffer layer. All of the above was achieved without thermal annealing. Finally, a 100 nm thick silver metallic contact was thermally deposited on the substrates as cathodes inside a vacuum thermal evaporator.
Reproducibility was evaluated using 100 devices with different amounts of experimental materials. Looking at the results, the team noted that the addition of OAm “significantly mitigated” drifts and improved device properties, with Cs10+OAm devices exhibiting the highest short-circuit current density, open-circuit voltage, and fill factor. with the smallest deviations in efficiencies.
The team claimed that the optimized Cs10+OAm device achieved “impressive efficiencies” of 23.2%. With an anti-reflective coating, it increased to 24.4%. He noted that the results surpassed the efficiencies achieved by previous perovskite solar cells (PSCs) processed at low temperature and room temperature (RT).
“Through a combination of characterization techniques, we have revealed the morphology and device physics of PSCs processed at RT. Finally, we demonstrate that non-annealing processing allows for the fabrication of high-quality perovskite films on sheet substrates,” the researchers conclude.
Details of the study appear in “ Room-temperature-processed perovskite solar cells surpassing 24% efficiency,” published in Joule . The researchers came from three institutions: the University of California, Santa Barbara, Koreas Pusan ??National University, and the Korea Electric Power Research Institute.
Looking ahead, the teams intend to work on integrated and indoor photovoltaic technologies. “Currently, we are focused on the development of efficient semi-transparent solar cells that achieve efficiencies greater than 12% while guaranteeing a level of transparency greater than 30%. These cells are designed for integration into windows of buildings, vehicles and greenhouses,” explains Nguyen.
“In addition, we are actively working on the development of indoor solar cells capable of achieving efficiencies greater than 40% under LED lighting conditions. “This advancement has the potential to provide renewable energy to power indoor devices and systems.” |
