Inhomogeneous Halide Anions Distribution along Out-of-Plane Direction in Wide-Bandgap Perovskite Solar Cells and Its Effect on Open Circuit Voltage Loss and Phase Segregation.

The large open circuit voltage (VOC) loss and phase segregation are two main obstacles hindering the development of wide-bandgap perovskite solar cells (PSCs). Even though substantial progress has been made through crystallization regulation and surface modification on perovskite, the mechanism of VOC loss and phase segregation has rarely been studied. In this paper, we first investigate the halide ions distribution along the out-of-plane direction and find the initial inhomogeneous distribution of halide ions during the crystallization process is an important reason. It leads to the formation of an unfavorable potential well in PSCs, resulting in VOC loss as well as generation of strong strain exacerbating phase segregation. Through introducing melatonin (MT) into perovskite precursors, a homogeneous distribution of halide anions is realized due to the well-regulated crystallization. Consequently, the treated PSCs exhibit an optimized power conversion efficiency (PCE) of 22.88% with a VOC loss as low as 0.38 V, which are the best values for wide-bandgap PSCs up to now.

Effect of acupuncture on neurovascular units after cerebral infarction in rats through PI3K/AKT signaling pathway.

OBJECTIVE: To study the effect of acupuncture on neurovascular units after cerebral infarction (CI) in rats through the phosphatidylinositol 3-hydroxy kinase/protein kinase B (PI3K/AKT) signaling pathway. METHODS: A total of 36 Sprague-Dawley rats were randomly divided into sham group (n = 12), model group (n = 12) and acupuncture group (n = 12). The external carotid artery was only exposed in model group, while the post-CI ischemia-reperfusion model was established using the suture method in the other 2 groups. After modeling, the rats in sham group and model group were fixed and sampled, while those in acupuncture group were treated with acupuncture intervention for 2 weeks and sampled. The neurological deficits of rats were evaluated using the Zea-Longa score, and the spatial learning and memory of rats were detected via water maze test. Moreover, the expressions of vascular endothelial growth factor (VEGF), growth associated protein-43 (GAP-43) and synuclein (SYN) in brain tissues were detected via immunohistochemistry, and the relative protein expressions of PI3K p85, PI3K p110 and p-AKT were detected via Western blotting. The messenger ribonucleic acid (mRNA) expressions of VEGF, GAP-43 and SYN were detected via quantitative polymerase chain reaction (qPCR). RESULTS: The Zea-Longa score was significantly increased in model group and acupuncture group compared with that in sham group (p < 0.05), while it significantly declined in acupuncture group compared with that in model group (p < 0.05). The escape latency was significantly prolonged and the times of crossing platform were significantly reduced in model group and acupuncture group compared with those in sham group (p < 0.05), while the escape latency was significantly shortened and the times of crossing platform were significantly increased in acupuncture group compared with those in model group (p < 0.05). The positive expressions of VEGF, GAP-43 and SYN were obviously increased in model group and acupuncture group compared with those in sham group (p < 0.05), while they were obviously increased in acupuncture group compared with those in model group (p < 0.05). Besides, model group and acupuncture group had significantly higher relative protein expressions of PI3K p85, PI3K p110 and p-AKT than sham group (p < 0.05), while acupuncture group also had significantly higher relative protein expressions of PI3K p85, PI3K p110 and p-AKT than model group (p < 0.05). The relative mRNA expressions of VEGF, GAP-43 and SYN were remarkably increased in model group and acupuncture group compared with those in sham group (p < 0.05), while they were remarkably increased in acupuncture group compared with those in model group (p < 0.05). CONCLUSION: Acupuncture promotes the repair of neurovascular units after CI in rats through activating the PI3K/AKT signaling pathway, thereby exerting a protective effect on neurovascular units.