Abstract
In order to move towards large-scale fabrication, perovskite solar cells need to detach themselves from strictly controlled environmental conditions and, to this end, fabrication in ambient air is highly desirable. Formamidinium iodide perovskite (FAPI) is one of the most promising perovskites but is also unstable at room temperature, which may make the ambient air deposition more difficult. Herein, we investigated different formulations of pure FAPI for the fabrication of perovskite solar cells (PSCs) in air. We found that formulations using a mixture of N,N-Dimethylformamide (DMF): N-methyl-2-pyrrolidone (NMP) and only dimethyl sulfoxide (DMSO) are suitable for the deposition in air. To fabricate inverted p-i-n solar cells, we tested different hole transporting layers (HTLs) and observed the effects on the wettability of the perovskite solution and on the performance. A self-assembly monolayer of 2PACz (2-(9H-Carbazol-9-yl)ethyl]phosphonic acid) was found to be the best option as a HTL, allowing us to achieve efficiencies >15% on both FTO and ITO.
Keywords:
FAPI; ambient air deposition; inverted perovskite solar cells; perovskite.
Grants and funding
The authors acknowledge the project “Sviluppo di celle solari a base di perovskite depositata in aria con additivi molecolari e polimerici”, Contract No. 3500056481, funded by ENI Spa and the project “nuovi Concetti, mAteriali e tecnologie per l’iNtegrazione del fotoVoltAico negli edifici in uno scenario di generazione diffuSa” [CANVAS], funded by the Italian Ministry of the Environment and the Energy Security, through the Research Fund for the Italian Electrical System (type-A call, published on G.U.R.I. n. 192 on 18 August 2022). A. R. and A. G. gratefully acknowledge the PNRR MUR project: “Integrated Infrastructure Initiative in Photonic and Quantum Sciences”—I-PHOQS (IR0000016), funded by the European Community-Next Generation EU; A. R. and A. G. gratefully acknowledge the project “MISSION INNOVATION, POA 2021–2023 Piattaforma Italiana Accelerata per i Materiali per l’Energia, IEMAP” funded by the Italian Ministry of the Environment and the Energy Security, MASE (CUP B82C21001820001). A. R. acknowledges the project Ricerca@Cnr VertiGrow (CUP B15F21004410005). A. R. gratefully acknowledges the PRIN 22 and PRIN PNRR 22 projects LEAD-OUT (2022B3C94E) and MASTER (P2022ZYTJY) funded by the European Community-Next Generation EU.