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.

Facile Synthesis of Aryl-Substituted Cycloarenes via Bismuth(III)Triflate-Catalyzed Cyclization of Vinyl Ethers

Cycloarenes are an essential class of polycyclic aromatic hydrocarbons with unique electronic structure,but their synthesis is very challenging.Herein,we report a facile synthetic strategy primarily involving macrocyclization by the Suzuki coupling reaction,followed by bismuth(III)triflate-catalyzed cyclization of vinyl ethers.By utilizing this approach,aryl-substituted soluble cycloarenes 7 and 8 with different sizes were obtained.X-ray crystallographic analysis revealed a slightly distorted backbone in the kekulene derivative 7 and a saddle-shaped skeleton in the octulene derivative 8.Bond length analysis suggested that both of the cycloarenes mainly complied with the Clar’s bonding model with dominant local aromaticity,which was also in accord with our NMR measurements and the theoretical calculations[nucleus-independent chemical shift[NICS],anisotropy of the induced current density(ACID),three-dimensional isochemical shielding surface(3D ICSS)].The optical properties were investigated by UV-Vis absorption and fluorescence spectral measurements.Our method opens opportunities to access various expanded and core-modified cycloarenes in the future.