Aqueous zinc‐ion batteries (ZIBs), with favorable merits of high security and low cost, have gained much interest in the energy storage field. However, their development is still in its infancy. Herein, V6O13 is investigated as aqueous ZIB cathodes with excellent Zn2+ storage performance, as compared with VO2 and V2O5. The intrinsic open structure of V6O13 with mixed‐valance states of vanadium (V4+/V5+) is favorable to enable fast Zn2+ ion diffusion and improved electronic conductivity, outperforming VO2 and V2O5. Significantly, the highly reversible phase transition of zinc vanadate (Zn0.25V2O5·H2O) can be detected during discharging, which enables the insertion of more Zn2+ ions into the host structure. As a result, V6O13 can exhibit enhanced electrochemical properties, including high capacity and excellent long‐term cyclability (206 mA h g−1 at 10 A g−1 after 3000 cycles).
We report on the visible and near-infrared electroluminescence
(EL) from the light-emitting device (LED) based on the erbium (Er)-doped
ZnO (ZnO:Er)/SiO2/n+-Si heterostructure, wherein
an ∼10 nm thick SiO2 intermediate layer serves as
the energy plateau for producing hot electrons, which come from n+-Si via the trap-assisted tunneling mechanism. These hot electrons
excite the doped Er3+ ions by inelastic collision, enabling
the Er-related EL from the aforementioned LED. More importantly, by
means of codoping the appropriate content of titanium (Ti) into the
ZnO:Er film, the aforementioned Er-related emissions can be significantly
enhanced. The density functional theory calculations indicate that
the Ti-codoping improves rather than degrades the symmetry of the
crystal field around the optically active Er3+ ions, hence
not increasing the intra-4f transition probabilities of Er3+ ions. However, it is found that Ti-codoping nearly eliminates the
segregation of Er3+ ions near the ZnO/SiO2 interface.
Moreover, Ti-codoping is derived to result in a number of Zn vacancies,
which provide the sites for incorporating Er3+ ions in
the ZnO matrix. For the above two reasons, the Ti-codoping promotes
the incorporation of optically active Er3+ ions into the
ZnO matrix, thus enhancing the EL from the aforementioned LED.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.