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We make a new type of bipolar Schottky diodes using the p-type La2/3Sr1/3VO3 (LSVO)/n-TiO2 heterostructure. The p-type LSVO metal thin films are grown on various substrates using radio frequency magnetron co-sputtering deposition. We find that the LSVO film grown on anatase TiO2 layer produce the lowest resistivity of 0.28 mΩ cm. We discover that the resistivity decreases with decreasing LSVO film thickness for LSVO/TiO2/Si structures. Hall measurements are performed and the dielectric functions of LSVO films are measured. The effective mass of LSVO/TiO2/Si is determined to be 2.54 ± 0.05 m0. The current-voltage curves of the Schottky diodes of p-LSVO/n-TiO2 is measured and is explained using band alignment diagram. We identify a new type of Schottky diode, where both electrons in n-TiO2 and holes in p-LSVO can flow under bias.

Recently, the flexibility and stability of perovskite solar cells (PSCs) with high power-conversion efficiency (PCE) have attracted the interest of many research. Reliable flexible transparent conductive electrodes (TCEs) and high stability at the perovskite/transport layers interface are vital for increasing the performance of flexible- and stable-PSCs. Herein, we develop PSCs with two-dimensional graphene (Gr) TCEs and MoS2 electron transport layers (ETLs). By modulating the number of layers (L) of Gr (LGr) and MoS2 (LMoS2), the maximum PCE of PSCs were 14.42 and 12.92% was achieved for PSCs fabricated on glass and polyethylene terephthalate substrates, respectively, at LGr = 2 and LMoS2 = 1. PSCs showed excellent stability as it lost only 18% of the initial PCE after 500 h. This is attributed to the improved ETL/perovskite interface. Moreover, the flexible PSCs retained 84% and 63% of the original PCE value after 1000 inner- and outer-bending cycles at a radius of curvature of 2 mm; thus, it is suitable for flexible devices.

Helicobacter pylori (H. pylori) infection causes chronic gastritis and gastric cancer. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is a key enzyme that catalyzes the oxidation of prostaglandin E2 (PGE2) to 15-keto-PGE2. 15-PGDH is speculated as a tumor suppressor as its expression has been frequently down-regulated in diverse human malignancies including gastric cancer. However, the molecular mechanisms underlying 15-PGDH down-regulation in tumorigenesis remain largely unknown. In the present study, we found that the 15-PGDH expression was down-regulated in rat gastric mucosa (RGM)-1 cells infected with H. pylori. H. pylori induced hypermethylation of 15-PGDH promoter. The hypermethylation level of 15-PGDH was higher in the stomach biopsy from H. pylori-infected patients with gastritis than those without H. pylori infection. Notably, H. pylori induced the expression of DNA methyl transferase (DNMT) 1 through generation of reactive oxygen species (ROS). In H. pylori-infected C57BL/6 mice, 15-PGDH expression was reduced while DNMT1 expression was increased in the stomach tissues. In conclusion, H. pylori induces DNA methylation of CpG islands in the 15-PGDH promoter through up-regulation of DNMT1 expression, which is attributable to the generation of ROS.