Researchers from EPFL, Soochow University, Chinese Academy of Sciences, Lomonosov Moscow State University, Luxembourg Institute of Science and Technology (LIST), Julius Maximilian University of Würzburg, Toin University of Yokohama, Southern University of Science and Technology, Xi’an Jiaotong University, North China Electric Power University and Toyota Motor Europe recently developed a solar panel relying on EPFL's record-breaking 25.32%-efficient 2D/3D perovskite solar cells unveiled in July 2023.
The group's research demonstrates a larger surface area of 27.22 cm2, achieving an impressive efficiency of 23.3%. In the paper, the scientists explain that the module's high efficiency was achieved thanks to a synergistic dopant-additive combination strategy aimed to improve the cell absorber's uniformity and crystallinity. They used, in particular, methylammonium chloride (MACl) as a dopant and a Lewis-basic ionic liquid known as 1,3-bis(cyanomethyl)imidazolium chloride ([Bcmim]Cl) as an additive.
The team said that this strategy effectively inhibits the degradation of the perovskite precursor solution (PPS), suppresses the aggregation of MACl and results in phase-homogeneous and stable perovskite films with high crystallinity and fewer defects.
The panel utilizes a cell with a substrate made of tin oxide (FTO), an electron transport layer made of titanium oxide (TiO2) and tin(IV) oxide (SnO2), a 3D perovskite layer, a 2D perovskite layer, a spiro-OMeTAD hole transport layer, and a metal contact based on gold (Au). The cell uses a 2D perovskite layer at the interface between the perovskite and the hole transport layer, which the researchers said can improve charge-carrier transport/extraction while suppressing ion migration.
The modules were encapsulated by glass-glass encapsulation technology combined with an edge seal of the module under UV light illumination.
Tested under standard illumination conditions, the panels achieved a certified efficiency of 23.30% and a stabilized efficiency of 22.97% over a 27.22-cm2 aperture area. According to the research group, it is the highest efficiency ever recorded for a perovskite solar module of this size. The perovskite solar modules also showed long-term operational stability, maintaining 94.66% of the initial efficiency after 1,000 h under continuous one-sun illumination at room temperature.
The scientists believe this module technology could be transferred into large-scale production and lead to the commercialization of perovskite-based photovoltaic technologies.
