No abstract

For emerging perovskite quantum dots (QDs), understanding the surface features and their impact on the materials and devices is becoming increasingly urgent. In this family, hybrid FAPbI 3 QDs (FA: formamidium) exhibit higher ambient stability, nearinfrared absorption and sufficient carrier lifetime. However, hybrid QDs suffer from difficulty in modulating surface ligand, which is essential for constructing conductive QD arrays for photovoltaics. Herein, assisted by an ionic liquid formamidine thiocyanate, we report a facile surface reconfiguration methodology to modulate surface and manipulate electronic coupling of FAPbI 3 QDs, which is exploited to enhance charge transport for fabricating high-quality QD arrays and photovoltaic devices. Finally, a record-high efficiency approaching 15 % is achieved for FAPbI 3 QD solar cells, and they retain over 80 % of the initial efficiency after aging in ambient environment (20-30 % humidity, 25 °C) for over 600 h.

No abstract

5-Hydroxymethylcytosine (5hmC) exists in DNA, RNA, and mitochondrial DNA (mtDNA) and plays an important role in many diseases. Specifically, 5hmC is involved in promoting gene expression, and this process is regulated by Tet enzymes. In this study, we identified that there is no difference in male mice and female mice at first; then we examined the levels of 5hmC in mtDNA and explored the relationship among 5hmC, mitochondrial gene expression and ATP production after acute brain ischemia. The abundance of mtDNA 5hmC was increased at 1 d and peaked at 2 d after ischemic injury, whereas that of mtDNA 5mC was unchanged. Furthermore, increased mitochondrial Tet2 expression was found to be responsible for the increase in mtDNA 5hmC. Tet2 inhibition decreased the mtDNA 5hmC abundance and increased the ATP levels in mitochondria, suggesting an association between the cellular ATP levels and mtDNA 5hmC abundance. We also demonstrated that mtDNA 5hmC increased the mRNA levels of mitochondrial genes after ischemia/reperfusion (I/R) injury.