Breakthrough in Perovskite Solar Cells Achieves Record Efficiency and Stability with Novel Stabilizer

In a significant leap forward for renewable energy technology, researchers have unveiled a novel approach that dramatically improves the performance and longevity of perovskite-organic tandem solar cells (TSCs). These advanced solar cells, which combine wide-bandgap (WBG) mixed-halide perovskites with organic materials, have long been plagued by issues such as initial halide-mixing inhomogeneity and light-induced halide segregation. These inherent instabilities have historically limited their power conversion efficiency and operational lifespan, posing a major hurdle to their widespread adoption. The innovative solution lies in the introduction of a pioneering photo-transformable additive, 4-[3-(trifluoromethyl)-3H-diazirin-3-yl]benzylamine (TDB), directly into the WBG perovskite precursor solution. This additive orchestrates a sophisticated two-stage stabilization strategy. During the critical crystallization phase, TDB actively enhances the initial homogeneity of the halide mixture by effectively suppressing the rapid precipitation of the bromine-rich phase and accelerating the crucial halide mixing process during annealing, laying a strong foundation for improved cell structure. The second, equally vital stage of TDB's action unfolds during the solar cell's operational illumination. Under light exposure, TDB undergoes a precise molecular transformation, forming a new chemical species. This transformed entity exhibits a remarkably stronger adsorption capability on the perovskite grain-boundary surfaces. This enhanced adhesion is crucial as it actively inhibits the formation of iodide-related defects, significantly suppresses defect-assisted carrier trapping, and curtails detrimental ion migration, thereby effectively mitigating the persistent problem of light-induced halide segregation that has challenged perovskite stability. The efficacy of this two-stage stabilization strategy was first demonstrated in a representative WBG perovskite solar cell (with an energy bandgap of 1.88 eV). This standalone cell achieved an impressive power conversion efficiency (PCE) of 20.01%, coupled with a high open-circuit voltage of 1.42 V and an excellent fill factor of 85.13%. Crucially, this cell also showcased significantly improved stability when subjected to continuous illumination, proving the additive's initial promise in enhancing fundamental perovskite properties. Building on this success, the researchers integrated this high-performing WBG perovskite solar cell into a monolithic perovskite-organic TSC. This integrated tandem cell achieved an outstanding peak PCE of 28.80%, with a certified steady-state PCE of an remarkable 28.04%. Perhaps even more critically for real-world applications, the perovskite-organic TSC demonstrated exceptional operational stability, retaining an impressive 90% of its initial PCE after a rigorous 625 hours of continuous operation under the demanding ISOS-L-1 protocol, setting a new benchmark for durability. This groundbreaking research, primarily conducted by scientists affiliated with the Chinese Academy of Sciences and other leading institutions, marks a pivotal moment in the development of next-generation solar energy technologies. By effectively overcoming the long-standing stability and efficiency limitations of perovskite solar cells, this innovation paves the way for the deployment of more cost-effective, high-performance, and durable solar energy solutions, accelerating the global transition towards sustainable power generation.