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An international team of researchers claims to have achieved optimal passivation in inverted perovskite solar cells by applying thin layers of low-dimensional perovskite on a 3D perovskite film. The resulting cell achieved an open circuit voltage of 1.19 V, a short circuit current density of 24.94 mA cm2 and a fill factor of 85.9%.
An international group of scientists led by Saudi Arabias King Abdullah University of Science and Technology (KAUST) has developed an inverted perovskite solar cell that incorporates low-dimensional perovskite layers at the top and bottom interfaces of the solar cell.
Inverted perovskite cells have a device structure known as a “pin,” in which the selective p-hole contact is located at the bottom of the intrinsic perovskite layer i with the electron transport layer n on top. . Conventional halide perovskite cells have the same structure but inverted, in a “nip” arrangement. In the pin architecture, the solar cell is illuminated through the electron transport layer (ETL) side; In the conventional nip structure, it is illuminated through the surface of the hole transport layer (HTL).
The researchers explained that optimal passivation in perovskite solar cells is typically achieved by applying thin layers of low-dimensional perovskite on a 3D perovskite film, and noted that it is essential to have perfect control over the thickness, purity and dimensionality of low-dimensional layers at the top and bottom of the 3D perovskites to minimize energy losses at these interfaces.
“After numerous tests, we identified the ligand that had the most effective interaction with three-dimensional perovskites for double-side passivation,” Randi Azmi, corresponding author of the research, told pv magazine .
“Perovskite solar cells with double-sided heterojunctions demonstrate a power conversion efficiency of 25.6%, ranking among the highest performing in their field. Following accelerated stability testing standards, efficiency decreased only 5% after 1,000 hours of exposure to real-world circumstances. This is essential to evaluate stability for commercialization,” added Stefaan De Wolf, Professor of Materials Science and Engineering at KAUST.
The scientists pointed out that the proposed technique aims to minimize the dissolution of the 2D ligands during the dissolution of the perovskite, in order to reinforce its interaction with the substrate, which, they added, allows the 2D ligands to be immobilized before the deposition of the perovskite. .
They fabricated a cell with a glass substrate and indium tin oxide (ITO), a layer of dimethoxy carbazole (Me-2PACz), a layer of 2D perovskite, a layer of 3D perovskite, a layer of 2D perovskite, a layer of electron transport of buckminsterfullerene (C60), a buffer layer of bathocuproin (BCP), and a silver (Ag) metal contact.
The scientists conducted a series of tests under standard lighting conditions and found that the device achieved a power conversion efficiency of 25.63%, an open circuit voltage of 1.19 V, a short circuit current density of 24, 94 mA cm2 and a fill factor of 85.9%. Performance was also tested by an unspecified “accredited test center,” which certified it achieved 25.0% efficiency, 1.17 V open circuit voltage, 25.0 mA short circuit current density. cm2 and a filling factor of 85.7%.
The cell was also able to maintain about 95% of its initial efficiency after 1,000 hours and 90% for the same number of hours with maximum power point tracking (MPPT). “This result indicates that double-sided 2D/3D heterojunctions have a significantly higher energy barrier for ion migration, which could also improve the stability of the perovskite crystal,” states the research group.
The novel cell design was presented in the study “ Double-side 2-dimensional/3-dimensional heterojunctions for inverted perovskite solar cells ,” which was recently published in Nature . The research group was composed of academics from South Koreas Ulsan National Institute of Science and Technology (UNIST) and the Chinese Academy of Sciences (CAS).
Another KAUST research group recently announced an inverted perovskite-silicon tandem solar cell with a 1 nm intermediate layer based on magnesium fluoride (MgFx), placed between the perovskite layer and the hole transport layer (HTL). , to reduce voltage losses. |
