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A novel all-pass slot microring resonator (SMRR), intended for label-free optical biosensing based on silicon-on-insulator platforms, is proposed. The sensor consists of a bent asymmetric directional coupler and an asymmetric-slot microring waveguide. The appropriate slot width of 140 nm is identified by the three-dimensional finite-difference time-domain (3D-FDTD) method for better light–matter interaction in applications. According to numerical calculations, the SMRR sensor with a footprint of 10 µm × 10 µm has a concentration sensitivity of 725.71 pm/% for sodium chloride (NaCl) solutions. The corresponding refractive index sensitivity is 403 nm/RIU (refractive index unit), which is approximately six times greater than that of traditional microring resonator sensors. A low detection limit of 0.129% is also achieved. This SMRR is an excellent candidate for label-free optical biosensors due to its compact structure and excellent sensing capability.

SnSe2 and SnSe nanocrystals were prepared using a simple solvothermal method by changing the molar ratio of SnCl[Formula: see text]2H2O and Se powder. When SnSe2 and SnSe are acted as lithium ion battery anodes, the SnSe hybrid structure shows more excellent electrochemical performance than that of SnSe2 interconnected nanosheet. It delivers a reversible capacity of 1023[Formula: see text]mAh[Formula: see text]g[Formula: see text] at a current density of 200[Formula: see text]mA[Formula: see text]g[Formula: see text], and maintaining a capacity of 498[Formula: see text]mAh[Formula: see text]g[Formula: see text] till 120 cycles. According to many present works, SnSe2 with interconnected thin nanosheet should possess more superior property than hybrid structured SnSe due to short charge transfer paths. However, in our research, the result is the opposite. Therefore, we consider that the superior electrochemical performance of SnSe is attributed to its highly reversible conversion reaction mechanism than SnSe2.

A green and natural biomass carbon with hollow structure was first reported derived from waste makeup cotton, which was prepared by facile pyrolysis and carbonisation in the nitrogen-filled vacuum tube furnace. Utilised as lithium-ion batteries (LIBs) anode materials, the hollow structure exhibits superior cycling and rate performance. At the current density of 100 mA g −1 , it demonstrates a reversible capacity of 340 mAh g −1 with the Coulombic efficiency of 58.8%, and the reversible capacity gradually increases to 450 mAh g −1 at 300 cycles, displaying long cycling stability. Even at a higher current density of 500 mA g −1 , the capacity can be maintained around 245 mAh g −1 after 150 cycles. Moreover, the hollow carbon exhibits excellent rate capability (222 mAh g −1 at an ultrahigh rate of 2000 mA g −1). This enhanced property can be attributed to its special hollow structure, which could provide fast lithium ions and electrons transfer path to facilitate the electrochemical reaction. The authors believe this work could help to design new carbon materials with green and environmental protection as anode materials for LIBs.