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Both spherical MnO as adsorbent and Ni nanoparticles as catalyzer, with highly exposed contact surface area in the carbon nanofibers, are successfully synthesized via electrospinning technology combined with carbothermal reduction. Compared with typical electrospun carbon nanofiber composites, the as-prepared C@Ni/MnO composite fibers as interlayer enable MnO and Ni to contact fully with polysulfides rather than provide local contact surface. With the sulfur loading of 1.6 mg cm

Eu3+ ions were grafted onto the surface of electrospun polyacrylonitrile (PAN) nanofibers through coordination effect between C N groups on PAN nanofibers and Eu3+ ions, and benzoic acid (BA) was introduced as an assistant ligand. The impacts of concentrations of Eu3+ ions and BA, and reaction time on the properties of final products were investigated. The results reveal that Eu3+ ions can be successfully grafted onto PAN nanofibers, but the fluorescence intensity of the obtained PAN@Eu3+ nanofibers is very weak. After BA is introduced as the assistant ligand, the fluorescence intensity of the obtained PAN@(Eu3+/BA) nanofibers is greatly stronger than that of PAN@Eu3+ nanofibers, and meanwhile, concentration quenching effect of Eu3+ ions can be effectively restrained. Furthermore, the superior structure of PAN@(Eu3+/BA) nanofibers not only brings the effective utilization of precious elemental europium, but also guarantees high mechanical strength.

Photothermal therapy (PTT) has presented its inherent application value in cancer treatment. Nevertheless, single-functional photothermal materials cannot meet the precise diagnosis and treatment of cancer. Therefore, it is important to design a nanocomposite that has both high therapeutic efficiency and multimodal imaging capabilities. In our work, a new nanostructure of gold nanorods (AuNRs) with silver shells decorated by BaGdF5:Yb3+,Er3+ nanoparticle was synthesized by a simple way. The biostability of AuNRs is increased by coating with silver shells, and the AuNR@Ag nanoparticles can be used as excellent surface enhanced Raman scattering (SERS) probe. Moreover, the modification of BaGdF5:Yb3+,Er3+ nanoparticles provides the possibility of real-time optical imaging of the tumor area. Under the irradiation of NIR laser, the AuNR@Ag/BaGdF5:Yb3+,Er3+ nanocomposites (NCs) have strong upconversion emission and excellent photothermal conversion efficiency. Meanwhile, the NCs show low cytotoxicity and good biocompatibility in MTT cytotoxicity test. Moreover, the NCs are also exceptional contrast agents for CT imaging. For in vitro photothermal therapy test, NCs show excellent killing efficiency on tumor cells. Therefore, the multifaceted research of AuNR@Ag/BaGdF5:Yb3+,Er3+ multifunctional nanomaterials provides a break for high-efficiency tumor photothermal therapy and multimodal imaging.

A new photosensitive dual-anisotropic conductive Janus film (PDCJF) is proposed for the first time. It is rationally designed and manufactured by facile electrospinning. PDCJF is firstly constructed using 2,7-dibromo-9-fluorenone (DBF) with photoconductive and luminescent properties. Janus nanofibers are respectively used as the building units to construct the top layer (T-PDCJF) and the bottom layer (B-PDCJF) of PDCJF. The two layers are tightly bonded to form PDCJF. Under light irradiation, there is photosensitive dual-anisotropic conduction in PDCJF, but there is no anisotropic conduction without light. Thus, the transition of PDCJF from mono-functional magnetism to tri-functionalities is realized under light and without light. The luminescence color of PDCJF is tunable and it emits white-light. This is made possible by modulating the amounts of luminescent substances and excitation wavelength. The microscopic Janus nanofibers used as building units and macroscopic Janus film structure ensure high photosensitive dual-anisotropic conduction and excellent fluorescence in PDCJF. The two-dimensional (2D) PDCJF is rolled to obtain three-dimensional (3D) Janus-type tubes and 2D plus 3D complete flag-like structures with exceptional multi-functionalities. The new findings can strongly guide in developing advanced multi-functional nanostructures.

The construction of photocatalyst with gradient band structure is guided by the principle of band gap engineering. Rational structural design is advanced and applied to construct a new-typed peculiarly structural and functional carbon-based [TiO2/C]//[Bi2WO6/C] Janus nanofiber modified by g-C3N4 nanosheets heterostructure photocatalyst (denoted as TB-JgHP). The flexible carbon-based [TiO2/C]//[Bi2WO6/C] Janus nanofiber with one side responding to ultraviolet light and the other capturing visible light is fabricated by conjugate electrospinning, and then g-C3N4 nanosheets are uniformly grown in-situ on the surface of the Janus nanofibers by using gas-solid reaction via gasification of urea. The optimized TB-JgHP possesses remarkable hydrogen evolution efficiency (17.48 mmol h−1 g−1) and methylene blue degradation rate (99.2%) under simulated sunlight illumination for 100 min, demonstrating prominent dual-functional characteristics. The enhanced photocatalytic performance benefits from the unique Janus structure as well as the synergistic effects among the triple heterostructures of TiO2 and Bi2WO6, g-C3N4 and TiO2, g-C3N4 and Bi2WO6. The formation of gradient band structure among heterostructures is more conducive to the multi-step separation of photo-induced electron-hole pairs and more effective absorption of light. Further, flexible self-standing carbon-based photocatalysts not only have outstanding electron transport performance, but also are easy to separate from solution with preeminent recyclable stability. Based on a series of characterization techniques, it is further proved that TB-JgHP has higher carrier separation efficiency than the counterpart contrast samples. The formation mechanism of TB-JgHP is proposed, and the construction technique is established. The design philosophy and construction technique presented in this work pave a new avenue for research and development of other heterostructure photocatalysts.

Novel Mn4+-activated red light-emitting phosphors, A2NaInF6:Mn4+ (A = K and NH4), have been designed and obtained through co-precipitation method. The phase identification, morphology and composition have been systematically investigated via X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometers (EDS), respectively. The excitation peaks of the red phosphors K2NaInF6:Mn4+ and (NH4)2NaInF6:Mn4+ are located at 300–550 nm, which means that (K,NH4)2NaInF6:Mn4+ can be applied in blue and ultraviolet chips. Excited by the blue light, the phosphors A2NaInF6:Mn4+ (A = K and NH4) exhibit red light emitting at 600–650 nm. The influence of reaction time, starting materials and the doping amounts of Mn4+ on the crystal structure and optical characteristic has been investigated. The temperature-dependent fluorescence results of K2NaInF6:Mn4+ samples have been also provided. The fabricated WLED with colour rendering index (Ra = 83.4) and low colour temperature (4444 K) is attained by using the prepared K2NaInF6:Mn4+ product. Therefore, the red light-emitting A2NaInF6:Mn4+ (A = K and NH4) phosphors could be regarded as good candidates for improving the performance of WLED.

Multifunctional core-shell nanostructure, which can be applied on bio-imaging and photothermal therapy (PTT), has attracted tremendous interest in recent years. Here, Ag@NaGdF4:Yb3+, Er3+ core-shell nanostructure incorporating luminescent, magnetic and photothermal conversion properties was prepared via a simple method. The as-prepared nanocomposites (NCs) exhibit uniform core-shell sphere morphology, green up-conversion luminescence (UCL), good paramagnetic and photothermal conversion behaviors. The luminescence resonance energy transfer (LRET) between Ag nanoparticles (NPs) and NaGdF4:Yb3+, Er3+ NPs were researched. The cytotoxicity test on HeLa cells using methyl thiazolyltetrazolium (MTT) assay shows good biocompatibility of the core-shell NCs. Moreover, in vitro computed tomography (CT) and UCL imaging studies and in vitro PTT of living assay suggest that the core-shell NCs can be used as theranostic nanoagents for dual-mode imaging guided PTT for tumor.