Discovering Process Dynamics for Scalable Perovskite Solar Cell Manufacturing with Explainable AI.

Large-area processing of perovskite semiconductor thin-films is complex and evokes unexplained variance in quality, posing a major hurdle for the commercialization of perovskite photovoltaics. Advances in scalable fabrication processes are currently limited to gradual and arbitrary trial-and-error procedures. While the in situ acquisition of photoluminescence (PL) videos has the potential to reveal important variations in the thin-film formation process, the high dimensionality of the data quickly surpasses the limits of human analysis. In response, this study leverages deep learning (DL) and explainable artificial intelligence (XAI) to discover relationships between sensor information acquired during the perovskite thin-film formation process and the resulting solar cell performance indicators, while rendering these relationships humanly understandable. The study further shows how gained insights can be distilled into actionable recommendations for perovskite thin-film processing, advancing toward industrial-scale solar cell manufacturing. This study demonstrates that XAI methods will play a critical role in accelerating energy materials science.

Regimes of motion of magnetocapillary swimmers.

The dynamics of a triangular magnetocapillary swimmer is studied using the lattice Boltzmann method. We extend on our previous work, which deals with the self-assembly and a specific type of the swimmer motion characterized by the swimmer's maximum velocity centred around the particle's inverse viscous time. Here, we identify additional regimes of motion. First, modifying the ratio of surface tension and magnetic forces allows to study the swimmer propagation in the regime of significantly lower frequencies mainly defined by the strength of the magnetocapillary potential. Second, introducing a constant magnetic contribution in each of the particles in addition to their magnetic moment induced by external fields leads to another regime characterized by strong in-plane swimmer reorientations that resemble experimental observations.

Optimal motion of triangular magnetocapillary swimmers.

A system of ferromagnetic particles trapped at a liquid-liquid interface and subjected to a set of magnetic fields (magnetocapillary swimmers) is studied numerically using a hybrid method combining the pseudopotential lattice Boltzmann method and the discrete element method. After investigating the equilibrium properties of a single, two, and three particles at the interface, we demonstrate a controlled motion of the swimmer formed by three particles. It shows a sharp dependence of the average center-of-mass speed on the frequency of the time-dependent external magnetic field. Inspired by experiments on magnetocapillary microswimmers, we interpret the obtained maxima of the swimmer speed by the optimal frequency centered around the characteristic relaxation time of a spherical particle. It is also shown that the frequency corresponding to the maximum speed grows and the maximum average speed decreases with increasing interparticle distances at moderate swimmer sizes. The findings of our lattice Boltzmann simulations are supported by bead-spring model calculations.

Malignant melanoma and nonmelanoma skin cancers in Northrhine-Westphalia, Germany: a patient- vs. diagnosis-based incidence approach.

BACKGROUND: Dermatologists have repeatedly criticized that the public health importance of nonmelanoma skin cancers is not appropriately reflected by the patient-based cancer incidence rates of population-based cancer registries. The aims of this study were to estimate the patient incidence rates of squamous cell carcinoma (SCC), basal cell carcinoma (BCC), and skin melanoma, and to study the effect of multiple primary skin tumors on the incidence rates. METHODS: We used a network of physicians covering a population of about 75,000 individuals to register all newly diagnosed invasive skin cancers (996 diagnoses in 796 patients), including BCC, SCC, and skin melanoma, from July 1998 to June 2003. We calculated age-standardized (world standard population) incidence rates (cases per 100,000 person-years) for the first diagnoses (called "patient incidence") and for any diagnoses of BCC, SCC, and skin melanoma (called "case incidence"). RESULTS: The patient incidence rates of BCC were 63.6 in men and 54.0 in women, and the case incidence rates of BCC were 82.7 and 71.1, respectively. The patient incidence rates of SCC were 17.4 in men and 9.7 in women, and the case incidence rates were 20.4 and 10.2, respectively. The patient and case incidence rates of skin melanoma were about the same at 13.6 in men and 18.5 in women. Twenty-five per cent of the BCC patients and 14% of the SCC patients suffered from more than one BCC and SCC, respectively, during the 5-year period. CONCLUSIONS: Patient incidence rates of BCC and SCC substantially underestimate the burden of nonmelanoma skin cancer in the population.