In this study, a highly sensitive trilayer photodetector using Co-doped ZnFe2O4 thin films annealed at 400 °C was synthesized successfully. Trilayer-photodetector devices with a film stack of 5 at % Co-doped-zinc-ferrite-thin-film/indium-tin-oxide on p+-Si substrates were fabricated by radio-frequency sputtering. The absorbance spectra, photoluminescence spectra, transmission electron microscopy images, and I–V characteristics under various conditions were comprehensively investigated. The outstanding performance of trilayer-photodector devices was measured, including a high photosensitivity of 181 and a fast photoresponse time with a rise time of 10.6 ms and fall time of 9.9 ms under 630 nm illumination. Therefore, the Co-doped ZnFe2O4 thin film is favorable for potential photodetector applications in visible light regions.

In lithium-ion batteries (LIBs), conversion-based electrodes such as transition-metal oxides and sulfides exhibit promising characteristics including high capacity and long cycle life. However, the main challenge for conversion electrodes to be industrialized remains on voltage hysteresis. In this study, Mn3O4 powder was used as an anode material for LIBs to investigate the root cause of the hysteresis. First, the electrochemical reaction paths were found to be dominated by Mn/Mn2+ redox couple after the first lithiation from galvanostatic charging/discharging (GCD) and cyclic voltammetry (CV) measurements. Then, the voltage hysteresis was proposed to be composed of reaction overpotential (∼0.373 V) and intrinsic overpotential (∼0.377 V), which were related to the diffusion behaviors according to CV, galvanostatic intermittent titration technique (GITT), and electrochemical impedance spectroscopy (EIS) analyses. Furthermore, results revealed that the formation of disparate phase distribution during lithiation and delithiation could be the root cause of the intrinsic overpotential of Mn3O4. These results were based on ultrahigh-resolution transmission electron microscopy (UHRTEM) and molecular dynamics (MD) simulation. It was expected that improving the diffusion behaviors of the systems could eliminate the voltage hysteresis of Mn3O4. In summary, this paper provides an explicit insight into the hysteresis for conversion-based Mn3O4 that could also be applied to other oxide systems and very crucial to reduce energy loss for commercializing oxides as anode materials in LIBs.

This study reports the optical and photoconductive characteristics of the Cu-Mg-Ni-Zn-Mn oxide thin films with and without post-annealing in air. The Cu-Mg-Ni-Zn-Mn oxide thin films reveal a narrow bandgap of...

In this study, three most commonly used commercial electrolyte compositions were selected to investigate the effect of different electrolyte solvents on lithium-ion batteries (LIBs) with MnO 2 anodes, including 1