Inverted perovskite solar cell with 2D/3D heterojunctions achieves 25.6% efficiency
An international research team claims to have achieved optimal passivation in inverted perovskite solar cells by applying thin layers of low-dimensional perovskite on top of 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 Arabia’s King Abdullah University of Science and Technology (KAUST) has developed an inverted perovskite solar cell incorporating low-dimensional perovskite layers at the solar cell’s top and bottom interfaces.
Inverted perovskite cells have a device structure known as “p-i-n”, in which hole-selective contact p is at the bottom of intrinsic perovskite layer i with electron transport layer n at the top. Conventional halide perovskite cells have the same structure but reversed, in an “n-i-p” layout. In p-i-n architecture, the solar cell is illuminated through the electron-transport layer (ETL) side; in the conventional n-i-p structure, it is illuminated through the hole‐transport layer (HTL) surface.
The researchers explained that optimal passivation in perovskite solar cells is typically achieved by applying thin layers of low-dimensional perovskite on top of a 3D perovskite film, and said it is critical to have perfect control over the thickness, purity, and dimensionality of the low-dimensional layers on the top and bottom of 3D perovskites to minimize the energetic losses at these interfaces.
“Perovskite solar cells with double-side heterojunctions demonstrate a power conversion efficiency of 25.6%, ranking among the top performers in their field. Following accelerated stability test standards, efficiency decreased by only 5% after 1,000 hours of exposure to real-world circumstances. This is critical for stability assessment for commercialization,” added Stefaan De Wolf, KAUST Professor of Material Science and Engineering.
The scientists said that the proposed technique is aimed at minimizing the dissolution of 2D ligands during perovskite solution, in order to strengthen their interaction with the substrate, which they added allows for immobilizing 2D ligands before perovskite depositio