Textured Perovskite/Silicon Tandem Solar Cells Achieving Over 30% Efficiency Promoted by 4-Fluorobenzylamine Hydroiodide

Monolithic textured perovskite/silicon tandem solar cells(TSCs)are expected to achieve maximum light capture at the lowest cost,potentially exhibiting the best power conversion efficiency.However,it is challenging to fabricate high-quality perovskite films and preferred crystal orientation on commercially textured silicon substrates with micrometersize pyramids.Here,we introduced a bulky organic molecule(4-fluorobenzylamine hydroiodide(F-PMAI))as a perovskite additive.It is found that F-PMAI can retard the crystallization process of perovskite film through hydrogen bond interaction between F^(−)and FA^(+)and reduce(111)facet surface energy due to enhanced adsorption energy of F-PMAI on the(111)facet.Besides,the bulky molecular is extruded to the bottom and top of perovskite film after crystal growth,which can passivate interface defects through strong interaction between F-PMA+and undercoordinated Pb^(2+)/I^(−).As a result,the additive facilitates the formation of large perovskite grains and(111)preferred orientation with a reduced trap-state density,thereby promoting charge carrier transportation,and enhancing device performance and stability.The perovskite/silicon TSCs achieved a champion efficiency of 30.05%based on a silicon thin film tunneling junction.In addition,the devices exhibit excellent longterm thermal and light stability without encapsulation.This work provides an effective strategy for achieving efficient and stable TSCs.

Suppressed recombination for monolithic inorganic perovskite/silicon tandem solar cells with an approximate efficiency of 23%

Potentially temperature-resistant inorganic perovskite/silicon tandem solar cells(TSCs)are promising devices for boosting efficiency past the single-junction silicon limit.However,undesirable non-radiative recombination generally leads to a significant voltage deficit.Here,we introduce an effective strategy using nickel iodide,an inorganic halide salt,to passivate iodine vacancies and suppress non-radiative recombination.NiI_(2)-treated CsPbI_(3-x)Br_(x) inor-ganic perovskite solar cells with a 1.80 eV bandgap exhibited an efficiency of 19.53%and a voltage of 1.36 V,corresponding to a voltage deficit of 0.44 V.Importantly,the treated device demonstrated excellent operational stability,maintaining 95.7%of its initial efficiency after maximum power point tracking for 300 h under continuous illumination in a N_(2) atmosphere.By combining this inorganic perovskite top cell with a narrower bandgap silicon bottom cell,we for the first time achieved monolithic inorganic perovskite/silicon TSCs,which exhibited an effi-ciency of 22.95%with an open-circuit voltage of 2.04 V.This work provides a promising strategy for using inorganic passivation materials to achieve efficient and stable solar cells.