New coating method boosts solar cell efficiency and stability to 22.45%
Researchers have cracked a long-standing problem in perovskite solar cells—uneven material distribution that degrades performance. By using a seed-layer technique to control how atoms arrange during manufacturing, they've achieved certified efficiency gains and created flexible solar panels. The breakthrough could accelerate commercialization of lighter, cheaper alternatives to silicon cells.
Originaltitel: Homogenous FACsPbI <sub>3</sub> Perovskite Solar Cells Enabled by a Seed‐Facilitated Cation Exchange Strategy
ABSTRACT While cesium incorporation into perovskites to form mixed‐cation perovskites (e.g., FACsPbI 3 ) can potentially improve the thermal stability, the effect is usually limited by the phase segregation resulting from cation inhomogeneity within FACsPbI 3 . Here, we successfully solve this problem by employing a novel seed‐facilitated cation exchange strategy, enabling homogeneous FACsPbI 3 films for efficient and stable photovoltaics. In this case, FAPbI 3 films are deposited on top of a substrate layer formed by Cs x PbI x+2 perovskite seeds, which regulate FACsPbI 3 crystal nucleation and growth. Among different Cs x PbI x+2 seeds, 0D Cs 4 PbI 6 is demonstrated to be the most effective in promoting a homogeneous Cs distribution by facilitating cation exchange and suppressing the formation of the yellow non‐perovskite phase. Based on the homogeneous FACsPbI 3 perovskite films, we achieve a 5 cm × 5 cm minimodule with a certified efficiency of 22.45%. In addition, our seed‐facilitated cation exchange strategy also modifies the buried interface between the perovskite layer and electron transport layer, making it possible to develop high‐quality flexible perovskite solar cells with a certified stabilized power output efficiency of 23.36%.