The Complex Degradation Mechanism of Copper Electrodes on Lead Halide Perovskites

Lead halide perovskite solar cells have reached power conversion efficiencies during the past few years that rival those of crystalline silicon solar cells, and there is a concentrated effort to commercialize them. The use of gold electrodes, the current standard, is prohibitively costly for commercial application. Copper is a promising low cost electrode material that has shown good stability in perovskite solar cells with selective contacts. Furthermore, it has the potential to be self passivating through the formation of CuI, a copper salt which is also used as a hole selective material. Based on these opportunities, we investigated the interface reactions between lead halide perovskites and copper in this work. Specifically, copper was deposited on the perovskite surface, and the reactions were followed in detail using synchrotron based and in house photoelectron spectroscopy. The results show a rich interfacial chemistry with reactions starting upon deposition and, with the exposure to oxygen and moisture, progress over many weeks, resulting in significant degradation of both the copper and the perovskite. The degradation results not only in the formation of CuI, as expected, but also in the formation of two previously unreported degradation products. The hope is that a deeper understanding of these processes will aid in the design of corrosion resistant copper based electrode

An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles

Large datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42, 400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences. © 2021, The Author(s)

Variants in the fetal genome near pro-inflammatory cytokine genes on 2q13 associate with gestational duration

The duration of pregnancy is influenced by fetal and maternal genetic and non-genetic factors. Here we report a fetal genome-wide association meta-analysis of gestational duration, and early preterm, preterm, and postterm birth in 84,689 infants. One locus on chromosome 2q13 is associated with gestational duration; the association is replicated in 9,291 additional infants (combined P= 3.96 x 10(-14)). Analysis of 15,588 mother-child pairs shows that the association is driven by fetal rather than maternal genotype. Functional experiments show that the lead SNP, rs7594852, alters the binding of the HIC1 transcriptional repressor. Genes at the locus include several interleukin 1 family members with roles in pro-inflammatory pathways that are central to the process of parturition. Further understanding of the underlying mechanisms will be of great public health importance, since giving birth either before or after the window of term gestation is associated with increased morbidity and mortality

The forward physics facility at the high-luminosity LHC

High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential

Extending the Compositional Space of Mixed Lead Halide Perovskites by Cs, Rb, K, and Na Doping

A trend in high performing lead halide perovskite solar cell devices has been increasing compositional complexity by successively introducing more elements, dopants, and additives into the structure; and some of the latest top efficiencies have been achieved with a quadruple cation mixed halide perovskite Cs_<i>x</i>FA_<i>y</i>MA_<i>z</i>Rb_{1‑<i>x</i>‑<i>y</i>‑<i>z</i>}PbBr_<i>q</i>I_3‑<i>q</i>. This paper continues this trend by exploring doping of mixed lead halide perovskites, FA_0.83MA_0.17PbBr_0.51I_2.49, with an extended set of alkali cations, i.e., Cs⁺, Rb⁺, K⁺, and Na⁺, as well as combinations of them. The doped perovskites were investigated with X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy, hard X-ray photoelectron spectroscopy, UV–vis, steady state fluorescence, and ultrafast transient absorption spectroscopy. Solar cell devices were made as well. Cs⁺ can replace the organic cations in the perovskite structure, but Rb⁺, K⁺, and Na⁺ do not appear to do that. Despite this, samples doped with K and Na have substantially longer fluorescence lifetimes, which potentially could be beneficial for device performance

Review of technology specific degradation in c-Si, CdTe, CIGS, dye sensitised, organic and perovskite solar cells in photovoltaic modules; understanding how reliability improvements in mature technologies can enhance emerging technologies

No abstract available