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This work encompasses a facile method for tailoring surface defects in electrospun TiO2 nanofibers by employing hydrogen plasma treatments. This amiable processing method was proven with SQUID, EPR, and XPS to be highly effective in generating oxygen vacancies, accompanied by the reduction of Ti4+ centers to Ti3+, resulting in the formation of black titania. The treatment temperature was found to affect the Ti3+/Ti4+ ratios and surface valence, while preserving the original 1D morphology of the titania fibers. Ab initio DFT calculations showed that a high concentration of oxygen vacancies is highly efficient in producing midgap states that enhance the system absorption over the whole visible range, as observed with UV/vis/NIR diffuse reflectance spectroscopy. Pristine TiO2 nanofibers produced a photocurrent density of ∼0.02 mA/cm2 at 1.23 V vs RHE, whereas the hydrogen plasma treatment resulted in up to a 10-fold increase in the photoelectrochemical performance.

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Thin-film organic−inorganic hybrid perovskite (MeNH 3 PbI 3 ) solar cells have displayed remarkably high photoconversion efficiencies, making their net-shaping as flexible device elements desirable for a number of applications. Simulations show greatly enhanced light absorption in perovskite fibers in comparison to their thin-film counterparts, which demand the processing of hybrid perovskites in the one-dimensional morphology. We report here on the single-step fabrication of MeNH 3 PbI 3 nanofibers on a customized electrospinning process performed under inert conditions. Our results demonstrate reproducible synthesis of electrospun fiber mats in which the fiber dimensions were tailored by adjusting the polymer (PVP) content. Photoluminescence studies on the perovskite fibers revealed a blue shift of the emission peak possibly due to strain or charge confinement effects. The hybrid perovskite nanofibers offer promising applications in flexible and stretchable optoelectronics.

Single phase rare earth pyrochlores, Ln2M2O7, were produced as nanofibers and thin films by electrospinning and spin-coating of chemical sols obtained from bimetallic metal-organic precursors, Ln III M II (O t Bu)5Py (Ln III = La, Pr, Nd, Sm, Er, Yb; M II = Ge, Sn, Pb; Py = pyridine). Compatibility of the metal ratio in the single-source compounds was confirmed by single crystal X-ray diffraction analyses and the ratio was preserved during the processing as the crystalline pyrochlore materials originated from an amorphous preceramic aggregate as confirmed by powder XRD and TEM studies. The photocatalytic activity of the Nd2Sn2O7 nanofibers was found to be significantly higher than that of TiO2. Nd2Sn2O7 thin films deposited on F:SnO2 as bilayered Nd2Sn2O7//Fe2O3 photoanodes showed superior photoelectrochemical (PEC) efficiency 2 for water splitting reaction with an over threefold higher photocurrent density than bare Fe2O3 photoanodes.