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Nonradiative charge recombination comprises a main pathway for energy losses that impedes the performance of all-inorganic perovskite solar cells. Grain boundaries (GBs) defects are unavoidable in low-temperature solution-processed perovskite polycrystalline films, but their role remains unclear. By performing ab initio nonadiabatic (NA) molecular dynamics simulations, we illustrate that electron–hole recombination in CsPbBr3 takes place over 100 ps, achieving a good agreement with experiment. Introduction of GBs into CsPbBr3 accelerates the recombination, while GBs doping with chlorine notably slow it down. Importantly, GBs do not create deep electron traps because they only narrow the band gap slightly. GBs localize electron wave functions at boundaries and activate additional phonon modes, leading to an enhanced NA coupling and a shortened coherence time. Consequently, the interplay between the three competitive factors accelerates the recombination by a factor of 2. Chlorine doping diminishes the mixing of electron and hole wave functions and reduces the NA coupling, which also shortens the coherence time further by introducing higher-frequency phonons, notably delaying the recombination. Our study establishes the atomistic mechanism that the acceleration and retardation in electron–hole recombination induced by GBs and chlorine doping in CsPbBr3 perovskite, providing new insights to improve the material properties via passivating the GB by chemical doping.

BackgroundHuman immunity to Schistosoma infection requires many years of exposure, and multiple infections and treatments to develop. Unlike humans, rhesus macaques clear an established schistosome infection naturally at the same time acquiring immunity towards re-infection. In macaques, schistosome egg production decreases after 8 weeks post-infection and by week 22, physiological impairment of the worm caused by unclarified antibody-mediated processes is observed. Since strong antibody responses have been observed against schistosome glycan antigens in human and animal infections, we here investigate if anti-glycan antibodies are associated with immunity against schistosome infections in macaques.MethodsWe used a microarray containing a large repertoire of glycoprotein- and glycolipid-derived glycans from different schistosome life stages to analyse anti-glycan serum IgG and IgM from S. japonicum-infected macaques during the course of infection and self-cure. We also used an in vitro schistosomula assay to investigate whether macaque sera containing anti-glycan antibodies can kill schistosomula.Conclusions/significanceAntibody responses towards schistosome glycans at week 4 post-infection were dominated by IgM while IgG was high at week 8. The profound increase in IgG was observed mainly for antibodies towards a large subset of glycans that contain (multi-)fucosylated terminal GalNAcβ1-4GlcNAc (LDN), and Galβ1-4(Fucα1–3)GlcNAc (LeX) motifs. In general, glycans with a higher degree of fucosylation gave rise to stronger antibody responses than non-fucosylated glycans. Interestingly, even though many IgG and IgM responses had declined by week 22 post-infection, IgG towards O-glycans with highly fucosylated LDN motifs remained. When incubating macaque serum with schistosomula in vitro, schistosomula death was positively correlated with the duration of infection of macaques; macaque serum taken 22 weeks post-infection caused most schistosomula to die, suggesting the presence of potentially protective antibodies. We hypothesize that IgGs against highly fucosylated LDN motifs that remain when the worms deteriorate are associated with infection clearance and the resistance to re-infection in macaques.

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This paper investigates the consensus problem of leader-following multi-agent systems with fractionalorder nonlinear dynamics. A typical event is defined as some error signals exceeding a given threshold. By applying Lyapunov functional approach and skills of computing function limit, consensus of the controlled multi-agent systems can be reached asymptotically. Meanwhile, the event-triggered algorithm can exclude Zeno behaviours. Finally, a numerical simulation is exploited to verify the effectiveness of the theoretical result.

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