Exploring CsPbI3 – FAI alloys: Introducing low-dimensional Cs2FAPb2I7 absorber for efficient and stable perovskite solar cellsстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 12 января 2022 г.
Аннотация:Among inorganic lead halide perovskites, cesium lead triiodide (CsPbI3) is considered the most promising forphotovoltaic applications. The material is a good absorber due to its narrow bandgap enabling efficient lightharvesting; however, the low stability of the “black” photoactive phases of CsPbI3 at low temperatures representsa major challenge for the practical application of this material. Herein, we report a new family of promisingperovskite-like 2D absorber materials produced by alloying CsPbI3 with formamidinium iodide (FAI). Using a setof complementary experimental techniques in combination with the density functional theory calculations wehave found that the introduction of FAI as overstoichiometric additive to CsPbI3 favors the formation ofperovskite-like phases with reduced dimensionality and improved stability. The optimal CsPbI3⋅xFAI (x = 0.5,0.6) (~Cs2FAPb2I7) material formulations do not undergo any phase transitions and do not show any signs ofdegradation upon continuous exposure to light for more than 1200 h. The observed high phase stability of theoptimal CsPbI3-FAI alloys has been explained through DFT calculations by using criteria for thermodynamicstability. The perovskite solar cells based on Cs2FAPb2I7 absorber material delivered light power conversionefficiency of ca. 13% and retained ~ 80% of the initial efficiency after 1200 h of continuous light soaking. Theobtained results set new efficiency and stability records for the Cs-rich low dimensional perovskite-like absorbermaterials. Further exploration of the newly emerging family of 2D materials stemming from the CsPbI3-FAI andsimilar alloys will pave the way to the development of a new generation of efficient and stable perovskite solarcells.