No abstract

Multifunctional and smart solar-blind photodetectors are of great significance for many applications, particularly for communications, optoelectronic circuits, and environmental risk monitoring. In this study, a wire-shaped photoanode of the solar-blind photoelectrochemical (PEC)-type photodetector based on an α-Ga2O3 nanorods/electrolyte solid/liquid heterojunction is realized. In photovoltaic devices, a junction generally comprises two different solid materials to facilitate the separation of photogenerated electron–hole pairs. Similarly, a solid/liquid junction is formed between the semiconductor and the electrolyte in a PEC photodetector. The apparent rectification characteristics of the dark current indicate that the energy bands bend at the α-Ga2O3 nanorods/electrolyte interface. The local electric field in the semiconductor effectively promotes the separation of carriers. The photodetectors exhibit a high light/dark current ratio ( Ilight/ Idark) of 68.7; fast rise and decay response times of 0.1 and 0.06 s, respectively; and a high responsivity of 11.2 mA/W (@230 nm) at zero bias. The wire-shaped photoanode is beneficial for realizing potential omnidirectional solar-blind detection.

Long cyclic stability and high rate performance have been the major challenges of lithium-ion batteries (LIBs). Composite metal oxides as a promising anode materials for LIBs have been studied extensively due to their high theoretical capacity, abundant reserves and large-scale production. Yet, their practical applications are seriously restricted by the volume change and poor conductivity. Herein, the ZnO/ TiO 2 /C nanofibers with different mole ratios of Ti/Zn were successfully synthesized by electrospinning method. The ZnO/TiO 2 /C nanofibers with a Zn/Ti mole ratio of 1:1 exhibited the highest reversible capacity of 912 mAh g -1 after 500 cycles at 100 mA g -1 . Meanwhile, the ZnO/TiO 2 /C nanofibers also possess an excellent rate capability even at a high current density up to 5 A g -1 . The Coulombic efficiency of ZnO/TiO 2 /C nanofibers has been steady at around 100% regardless of rate and long cycle. The good electrochemical properties of ZnO/TiO 2 /C nanofibers with a Zn/Ti mole ratio of 1:1 may be attributed to the synergistic effect of C and the introduction of interface between ZnO and TiO 2 . Overall, the ZnO/TiO 2 /C nanofibers were demonstrated unexpectedly high specific capacity retention, high reversibility and excellent rate performance as the anode materials of LIBs.

Metal sulfides are often used as cathode materials for lithium-ion batteries (LIBs) owing to their high theoretical specific capacity; however, excessively fast capacity decay during charging/discharging and rapid shedding during cycling limits their practical application in batteries. In this study, we proposed a strategy using plasma treatment combined with the solvothermal method to prepare cobalt sulfide (Co1−x S)-carbon nanofibers (CNFs) composite. The plasma treatment could introduce oxygen-containing polar groups and defects, which could improve the hydrophilicity of the CNFs for the growth of the Co1−x S, thereby increasing the specific capacity of the composite electrode. The results show that the composite electrode present a high discharge specific capacity (839 mAh g−1 at a current density of 100 mA g−1) and good cycle stability (the capacity retention rate almost 100% at 2000 mA g−1 after 500 cycles), attributing to the high conductivity of the CNFs. This study proves the application of plasma treatment and simple vulcanization method in high-performance LIBs.

The multifunctional and smart ultraviolet photodetectors are of great significance and necessity for applications in many fields, especially in health and environmental risk monitoring. Hence, a wire-shaped photoelectrochemical type ultraviolet photodetector based on photoanode of TiO2 nanotube arrays (TNAs) fabricated by electrochemical anodization is demonstrated in this work. The TNAs can provide direct pathways for carriers and large internal surface area. The assembled UV detector presented a high photocurrent density of 110  μA cm−2, a high ON/OFF ratio of 467, and a fast rise and decay response time of 13 and 19 ms for the optimal thickness of the photoanode of TNAs. Moreover, the detectors also exhibited visible-blind characteristics and an excellent linear response even under weak irradiation (20–100  μW cm−2). The results are beneficial to realizing omnidirectional and wearable optoelectronic devices.