Methylamine-Modified Acetonitrile as Solvent to Ease the Fabrication and Upscaling of p-i-n Perovskite Solar Cells

Despite the easy fabrication of perovskites by a solvent-based technique, solvent and additive engineering is crucial in obtaining high efficiencies on large areas. In this work, we report the advantage of perovskite ink prepared from methylammonium-modified acetonitrile (MA-ACN) solvent for deposition on hydrophobic hole transport material (HTM). A reduction of the contact angle with the substrate is obtained, enabling a direct perovskite deposition, while a pretreatment step is required for the usual dimethylformamide (DMF)-dimethyl sulfoxide (DMSO)-based ink. A champion efficiency of 19.3% is achieved with poly(triaryl)amine (PTAA), exhibiting remarkably high values of V-oc > 1.1 V and FF > 80%, with the simple MAPbI(3) perovskite. Its association with Poly-TPD, P3HT, CuSCN, and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) HTM is also investigated. For the last two, compatibility issues are highlighted. Finally, we report an 18.5% efficiency champion device with the perovskite deposited by a doctor blade without any annealing, air blading, or antisolvent during the deposition, showing the high potential of such ink for upscaling perovskite devices.