Passivation of Inverted Perovskite Solar Cells by Trifluoromethyl- Group-Modified Triphenylamine Dibenzofulvene Hole Transporting Interfacial Layers

In this work, we synthesized trifluoromethyl group series modified triphenylamine dibenzofulvenes, named as CC-1-3, as a hole transporting interfacial layer to obtain well-matched energy levels and long-term stability features in NiOx-based inverted perovskite solar cells. The optical and thermal properties of these new compounds were investigated. All the compounds were combined with NiOx and formed layer by layer as hole transporting layers (HTLs). The morphology, energy level, and charge transfer resistance were all compared. The NiOx/CC-3 bilayer-based architecture improved the energy level alignment, film morphology, crystallinity, and hole transportation, allowing for a high-quality perovskite layer and interfacial contact behavior. As a result, this inverted cell significantly improved open-circuit voltage (VOC), short current density (JSC), fill factor (FF), and power conversion efficiency (PCE) values up to 21.66 mA cm-2, 1.105 V, 79.33%, and 19.82%, respectively. Remarkably, the NiOx/CC-3 device had negligible hysteresis and long-term stability, retaining over 90% of its original efficiencies under argon and over 80% in the ambient atmosphere after 40 days. This paper shows a new chemical design, particularly for the trifluoromethyl group effect, and a complete understanding of the bilayer HTL technique and its promise for producing efficient cell performance.

Automated summary

In this study, trifluoromethyl group series modified triphenylamine dibenzofulvenes (CC-1-3) were synthesized as a hole transporting interfacial layer for NiOx-based inverted perovskite solar cells to achieve well-matched energy levels and long-term stability features. The optical and thermal properties of these compounds were investigated, and they were combined with NiOx to form hole transporting layers (HTLs). The NiOx/CC-3 bilayer-based architecture improved energy level alignment, film morphology, crystallinity, and hole transportation, resulting in significantly improved cell performance.