2 research outputs found
NOBF<sub>4</sub>‑Functionalized Au–Fe<sub>3</sub>O<sub>4</sub> Nanoheterodimers for Radiation Therapy: Synergy Effect Due to Simultaneous Reactive Oxygen and Nitrogen Species Formation
Snowman-shaped
Au–Fe<sub>3</sub>O<sub>4</sub> nanoheterodimers
were synthesized by thermal decomposition of iron oleate on presynthesized
Au nanoparticles. Subsequently performed ligand exchange with nitrosyl
tetrafluoroborate provided water solubility and enabled X-ray-induced
NO release. These Au–Fe<sub>3</sub>O<sub>4</sub> nanoheterodimers
combine high-<i>Z</i> material with catalytically active
Fe<sub>3</sub>O<sub>4</sub> surfaces and, moreover, plasmonic properties
with superparamagnetic performance. We could establish synergetic
interactions between X-radiation and both the Au and Fe<sub>3</sub>O<sub>4</sub> surfaces, which resulted in the simultaneous production
of the nitric oxide radical at the Fe<sub>3</sub>O<sub>4</sub> surface
and the superoxide radical at the Au surface. The surface-confined
reaction between these radicals generated peroxynitrite. This highly
reactive species may cause nitration of mitochondrial proteins and
lipid peroxidation and induce DNA strand breaks. Therefore, high concentrations
of peroxynitrite are expected to give rise to severe cellular energetic
derangements and thereupon entail rapid cell death. As providing a
common platform for X-ray-induced formation of the highly reactive
radical nitric oxide, superoxide, and peroxynitrite, nitrosyl tetrafluoroborate
functionalized Au–Fe<sub>3</sub>O<sub>4</sub> nanosnowmen were
shown to exhibit excellent performance as X-ray-enhancing agents in
radiation therapy
Understanding and controlling the evolution of nanomorphology and crystallinity of organic bulk-heterojunction blends with solvent vapor annealing
Solvent vapor annealing (SVA) has been shown to significantly improve the device performance of organic bulk-heterojunction solar cells, yet the mechanisms linking nanomorphology, crystallinity of the active layer, and performance are still largely missing. Here, the mechanisms are tackled by correlating the evolution of nanomorphology, crystallinity, and performance with advanced transmission electron microscopy methods systematically. Model system of DRCN5T:PC71BM blends are SVA treated with four solvents differing in their donor and acceptor solubilities. The choice of solvent drastically influences the rate at which the maximum device efficiency establishes, though similar values can be achieved for all solvents. The donor solubility is identified as a key parameter that controls the kinetics of diffusion and crystallization of the blend molecules, resulting in an inverse relationship between optimal annealing time and donor solubility. For the highest efficiency, optimum domain size and single-crystalline nature of DRCN5T fibers are found to be crucial. Moreover, the π–π stacking orientation of the crystallites is directly revealed and related to the nanomorphology, providing insight into the charge carrier transport pathways. Finally, a qualitative model relating morphology, crystallinity, and device efficiency evolution during SVA is presented, which may be transferred to other light-harvesting blends.</p