Efficient and Stable Inverted Perovskite Solar Modules Enabled by Solid-Liquid Two-Step Film Formation

A considerable efficiency gap exists between large-area perovskite solar modules and small-area perovskite solar cells.The control of forming uniform and large-area film and perovskite crystallization is still the main obstacle restricting the efficiency of PSMs.In this work,we adopted a solid-liquid two-step film formation technique,which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovskite films.This method possesses the advantages of integrating vapor deposition and solution methods,which could apply to substrates with different roughness and avoid using toxic solvents to achieve a more uniform,large-area perovskite film.Furthermore,modification of the NiO_(x)/perovskite buried interface and introduction of Urea additives were utilized to reduce interface recombination and regulate perovskite crystallization.As a result,a large-area perovskite film possessing larger grains,fewer pinholes,and reduced defects could be achieved.The inverted PSM with an active area of 61.56 cm^(2)(10×10 cm^(2)substrate)achieved a champion power conversion efficiency of 20.56%and significantly improved stability.This method suggests an innovative approach to resolving the uniformity issue associated with large-area film fabrication.

Self-assembled monolayer enabling improved buried interfaces in blade-coated perovskite solar cells for high efficiency and stability

Despite the rapidly increased power conversion efficiency(PCE)of perovskite solar cells(PVSCs),it is still quite challenging to bring such promising photovoltaic technology to commercialization.One of the challenges is the upscaling from small-sized lab devices to large-scale modules or panels for production.Currently,most of the efficient inverted PVSCs are fabricated on top of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine](PTAA),which is a commonly used hole-transporting material,using spin-coating method to be incompatible with large-scale film deposition.Therefore,it is important to develop proper coating methods such as blade-coating or slot-die coating that can be compatible for producing large-area,high-quality perovskite thin films.It is found that due to the poor wettability of PTAA,the blade-coated perovskite films on PTAA surface are often inhomogeneous with large number of voids at the buried interface of the perovskite layer.To solve this problem,self-assembled monolayer(SAM)-based hole-extraction layer(HEL)with tunable headgroups on top of the SAM can be modified to provide better wettability and facilitate better interactions with the perovskite coated on top to passivate the interfacial defects.The more hydrophilic SAM surface can also facilitate the nucleation and growth of perovskite films fabricated by blade-coating methods,forming a compact and uniform buried interface.In addition,the SAM molecules can also be modified so their highest occupied molecular orbital(HOMO)levels can have a better energy alignment with the valence band maxima(VBM)of perovskite.Benefitted by the high-quality buried interface of perovskite on SAM-based substrate,the champion device shows a PCE of 18.47%and 14.64%for the devices with active areas of 0.105 cm^(2) and 1.008 cm^(2),respectively.In addition,the SAM-based device exhibits decent stability,which can maintain 90%of its initial efficiency after continuous operation for over 500 h at 40℃ in inert atmosphere.Moreover,the SAM-based perovskite mini-module exhibits a PCE of 14.13%with an aperture area of 18.0 cm^(2).This work demonstrates the great potential of using SAMs as efficient HELs for upscaling PVSCs and producing high-quality buried interface for large-area perovskite films.