Outstanding Fill Factor in Inverted Organic Solar Cells with SnO 2 by Atomic Layer Deposition.

Transport layers are of outmost importance for thin film solar cells, determining not only their efficiency but also their stability. To bring one of these thin film technologies towards commercialization, many factors besides efficiency and stability become important, including the ease of deposition in a scalable manner and the cost of the different material's layers. Herein, highly efficient organic solar cells (OSCs), in the inverted structure (n-i-p), are demonstrated by using as electron transport layer (ETL) tin oxide (SnO 2 ) deposited by atomic layer deposition (ALD). ALD is an industrial grade technique which can be applied both at the wafer level but also in a roll-to-roll configuration. A champion efficiency of 17.26% and a record FF of 79% is shown by PM6:L8-BO OSCs when using ALD-SnO 2 as ETL. These devices outperform not only solar cells with SnO 2 nanoparticles casted from solution (PCE 16.03%, FF 74%) but also those utilizing the more common sol-gel ZnO (PCE 16.84%, FF 77%). The outstanding results are attributed to a reduced charge carrier recombination at the interface between the ALD-SnO 2 film and the active layer. Furthermore, a higher stability under illumination is demonstrated for the devices with ALD-SnO 2 in comparison with those utilizing ZnO. This article is protected by copyright. All rights reserved.