Perovskite solar cell fabrication via scalable thermal‐assisted and meniscus‐guided bar‐coating method in open air

Abstract

AbstractBackgroundPerovskite‐based solar cell is getting great attention as a promising candidate for future solar cell technology, since high power conversion efficiency above 25.5% have been demonstrated for small scale PSCs from films prepared mainly by spin‐coating method, which is not feasible for large area film preparation. Scalable and cost‐effective film fabrication techniques are urgently needed for the commercialization of perovskite solar cells.ObjectiveTo develop a process from which large‐area, high quality and unifoem perovskite films, as well as the hole‐transporting layer films, can be prepared in a simple and cheap way for the practical application and mass production of perovskite solar cells.MethodsLarge‐area electron‐transporting layer layers of mp‐TiO2 and c‐TiO2 were prepared on the FTO substrate by the solution‐shearing method. Then the 10 × 10 cm2 perovskite film was prepared by using a bar‐coater from perovskite precursor solution in ACN/MA solvent system under optimized conditions. The spiro‐OMeTAD film was also prepared by bar‐coating process. Standard‐sized pieces (1.5 × 1.8 cm2) were cut and the Ag metal electrode (80 nm) was deposited through a shadow mask in a thermal evaporation system for device evaluation.ResultsThe large crystalline grains and pinhole‐free perovskite film obtained were fully characterized to show better film properties compared to that from the spin‐coated film, and appeared less sensitive to moisture. A higher PCE of 19.72% was achieved for standard‐sized devices fabricated from the bar‐coated perovskite film with spiro‐OMeRAD film spin‐coated on top, or an excellent PCE of 18.10% was obtained with bar‐coated spiro‐OMeTAD layer on top.ConclusionsThis work demonstrates that the simple and scalable process of bar‐coating can offer high quality and homogeneous films of perovskite and spiro‐OMeTAD respectively. It is compatible with the R2R process and useful in realizing the commercialization of PSC technology.