Despite the notable success of hybrid halide perovskite-based solar cells, their long-term stability is still a key-issue. Aside from optimizing the photoactive perovskite, the cell design states a powerful lever to improve stability under various stress conditions. Dedicated electrically conductive diffusion barriers inside the cell stack, that counteract the ingress of moisture and prevent the migration of corrosive halogen species, can substantially improve ambient and thermal stability. Although atomic layer deposition (ALD) is excellently suited to prepare such functional layers, ALD suffers from the requirement of vacuum and only allows for a very limited throughput. Here, we demonstrate for the first time spatial ALD-grown SnO at atmospheric pressure as impermeable electron extraction layers for perovskite solar cells. We achieve optical transmittance and electrical conductivity similar to those in SnO grown by conventional vacuum-based ALD. A low deposition temperature of 80 °C and a high substrate speed of 2.4 m min yield SnO layers with a low water vapor transmission rate of ∼10 gm day (at 60 °C/60% RH). Thereby, in perovskite solar cells, dense hybrid Al:ZnO/SnO electron extraction layers are created that are the key for stable cell characteristics beyond 1000 h in ambient air and over 3000 h at 60 °C. Most notably, our work of introducing spatial ALD at atmospheric pressure paves the way to the future roll-to-roll manufacturing of stable perovskite solar cells.

Lead halide perovskite solar cells afford high power conversion efficiencies, even though the photoactive layer is formed in a solution process. At the same time, solution processing may impose some severe dewetting issues, especially if organic, hydrophobic charge transport layers are considered. Ultimately, very narrow processing windows with a relatively large spread in device performance and a considerable lab-to-lab variation result. Here, we unambiguously identify dimethylsulfoxide (DMSO), which is commonly used as a co-solvent and complexing agent, to be the main reason for dewetting of the precursor solution on hydrophobic hole transport layers, such as polytriarylamine, in a gas-quenching-assisted deposition process. In striking contrast, we will show that N-methyl-2-pyrrolidon (NMP), which has a lower hydrophilic–lipophilic-balance, can be favorably used instead of DMSO to strongly mitigate these dewetting issues. The resulting high-quality perovskite layers are extremely tolerant with respect to the mixing ratio (NMP/dimethylformamide) and other process parameters. Thus, our findings afford an outstandingly robust, easy to use, and fail-safe deposition technique, yielding single (MAPbI3) and double (FA0.94Cs0.06PbI3) cation perovskite solar cells with high efficiencies (∼18.5%). Most notably, the statistical variation of the devices is significantly reduced, even if the deposition process is performed by different persons. We foresee that our results will further the reliable preparation of perovskite thin films and mitigate process-to-process variations that still hinder the prospects of upscaling perovskite solar technology.

This paper approaches the evaluation of intelligent agents for the reduction and avoidance of spontaneous traffic jams, which arise without evident reason. Individual vehicles are regarded as intelligent agents that act autonomously. The basis of this work is the Nagel-Schreckenberg (NaSch) model. Its extensions by the velocity-dependent randomization (VDR) model and multiple lanes allow us to simulate realistic traffic and congestion situations on two-lane motorways. Our concept is applied to the model and analyzed by fundamental diagrams and the average velocity, for example. The results of this paper reveal that traffic congestions are avoided when using swarm intelligence in all vehicles since human behavior, especially misbehavior, is eliminated and the velocities determined by the intelligent vehicle are directly realized. Moreover, an amount of 30% of intelligent vehicles has a significantly positive impact on traffic flow.