Solar-to-Electric Performance Enhancement by Titanium Oxide Nanoparticles Coated with Porous Yttrium Oxide for Dye-Sensitized Solar Cells

TiO₂–Y₂O₃ core–shell nanoparticles for dye-sensitized solar cells (DSSCs) have been fabricated by a solvothermal technique. The heterostructure of TiO₂ nanoparticles coated with porous Y₂O₃ is confirmed with transmission electron microscopy. The bonding of the Y₂O₃ coating on the TiO₂ surface is quantitatively analyzed in terms of the Lifshitz–van der Waals and electrostatic contributions to the surface free energy of the particles. TiO₂ and Y₂O₃ constitute a core–shell heterojunction because the Fermi levels merge; this increases the open-circuit voltage. Higher recombination resistances are obtained in DSSCs with porous Y₂O₃-coated TiO₂ compared with those in the reference cells, indicating “backscattering” inhibition of the porous Y₂O₃ barrier on TiO₂ nanoparticles. Moreover, smaller transport resistances and longer electron lifetimes are achieved in DSSCs with TiO₂–Y₂O₃ core–shell nanoparticles. Compared with a reference cell, the <i>V</i>_OC of a DSSC with a partial Y₂O₃ coating on the surface of the TiO₂ nanoparticles improves from 683 to 738 mV and the <i>J</i>_sc from 14.15 to 15.35 mA·cm^–2, whereas the conversion efficiency increases by 15.2%

Chrysamides A–C, Three Dimeric Nitrophenyl <i>trans</i>-Epoxyamides Produced by the Deep-Sea-Derived Fungus <i>Penicillium chrysogenum</i> SCSIO41001

Three dimeric nitrophenyl <i>trans</i>-epoxyamides, chrysamides A–C (<b>1</b>–<b>3</b>), were obtained from the deep-sea-derived fungus <i>Penicillium chrysogenum</i> SCSIO41001. Their structures were characterized by spectroscopic analysis, electronic circular dichroism computations, and X-ray single-crystal diffraction analysis. Notably, compound <b>1</b> possesses a novel centrosymmetric dimer skeleton featuring an unprecedented 7-oxa-2,5-diazabicyclo[2.2.1]­heptane ring system, which represents the first example of dimeric nitrophenyl <i>trans</i>-epoxyamide in nature. Compound <b>3</b> suppresses the production of proinflammatory cytokine interleukin-17. A possible biosynthetic pathway of <b>1</b>–<b>3</b> was proposed