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Optimization of the host lattice is a novel strategy to achieve efficient up‐conversion luminescence (UCL) with multi‐peak full‐spectrum emission. Herein, lattice optimization is performed in a non‐vacuum sulfur‐rich environment, where the ultra‐low phonon energy NaYS2 heterogeneous phase is forced to intergrow, which overcomes the limitations of the conventional vacuum preparation method and achieves high‐efficient UCL. Remarkably, the lattice sites are preferentially occupied by S2−, which causes lattice distortion and generates layered NaYS2/Y2O2S hybrid crystalline with high inversion asymmetry to reconfigure excitation mechanism and exhibit distinct luminescence centers at the multi‐peak full‐spectrum. Moreover, owing to longer lifetime of excited state energy levels of Er3+ after lattice modification and ordered segregation of Er3+ in the YS6 layer restricting the negative energy exchange process, the luminescence intensity is increased by about six times, and the remodeling of full‐spectrum‐efficient UCLs is realized. This work reports an innovative approach for lattice optimization and a facile preparation of ternary sulfides, which provides a new direction for achieving highly efficient UCLs with promising applications in biomedical imaging, near‐infrared detection, and temperature sensing synergy. [ABSTRACT FROM AUTHOR]

Perovskites with ultra‐low phonon energy have excellent radiation properties, while the population distribution of its luminescent initial state needs to be facilitated to further optimize the stokes fluorescence of Er3+ under high‐energy photons excitation. Herein, UV excitability of Er3+ is remodeled by building an energy transfer channel from Sb3+ to Er3+ in Cs2NaInCl6 (CNIC) microcrystal to realize the enhancement of stokes fluorescence of Er3+. Under UV excitation, the breakthrough boost of Er3+ is observed in Cs2NaInCl6:Sb3+‐Er3+ (CNIC:Sb‐Er), and the sensitization coefficient from Sb3+ to Er3+ in CNIC is derived to be as high as 112. Moreover, CNIC:Sb‐Er is embedded into functional fibers to enhance the crystal stability and the composite flexibility, which form fluorescence fibers with strong radiation transition probability. Finally, a high‐precision temperature sensing is achieved based on FIR (fluorescence intensity ratios) technology, and the maximum relative sensitivities of CNIC:Sb‐Er phosphors and CNIC:Sb‐Er/PAN fibers reach 1.13 and 1.10% K−1, respectively, indicating that CNIC:Sb‐Er and CNIC:Sb‐Er/PAN fibers have potential applications in optical temperature sensors. [ABSTRACT FROM AUTHOR]

Effective utilization of solar energy through photocatalytic oxidation is of great significance for environmental restoration and sustainable development. In order to realize the rapid separation of electron–hole pairs and improve the photocatalytic degradation activity, a multifunctional CsPbBr3/BiOI/TiO2 nanofiber photocatalyst with a symmetric double heterojunction structure is synthesized by combining electrospinning, hydrothermal and wet impregnation methods. Compared with powder photocatalysts, polyacrylonitrile (PAN) composite fibers work as a carrier offering the advantages of reusability, excellent flexibility, thermal stability, a controlled structure and a large specific surface area. Benefiting from the effective interfacial charge transfer and enhanced visible-light absorption, the obtained CsPbBr3/BiOI/TiO2@PAN nanofibers exhibit superior photocatalytic efficiency for rhodamine B, tetracycline hydrochloride, phenol and bisphenol A under simulated sun-light irradiation. Based on fluorescence intensity ratio (FIR) thermometry, the emission peaks of CsPbBr3 at 516 nm and PAN at 479 nm can be utilized for accurate non-contact temperature monitoring and real-time thermal feedback in complex degradation systems, and the maximum relative sensitivity SR is obtained as 0.0117 K−1 at 353 K. In conclusion, multi-selective photocatalysis fibers with real-time optical thermometry properties provide new application prospects for water purification in extremely harsh environments. [ABSTRACT FROM AUTHOR]

Herein, an electrospinning porous nanofiber with large specific surface area, excellent flexibility, remarkable tensile strength, and high stability of thermal degradation has been developed by loading Ho3+/Yb3+ co-doped BiOBr/g-C3N4 (BHY/CN) heterojunction photocatalysts on polyacrylonitrile (PAN) nanofibers. The optimized BHY/CN-2 nanofiber demonstrates outstanding photocatalytic activity for the degradation of 98.83% tetracycline (TC, 60 min) and 99.06% rhodamine B (RhB, 90 min) under simulated sunlight irradiation, and maintains a high level of reusability and recycling stability in three cycles. In addition, temperature monitoring of the catalytic degradation process can be feedback by (5F4, 5S2) → 5I8 and 5F5 → 5I8 radiation transitions of Ho3+ with excellent sensitivity. More importantly, the nanofiber luminescence performance is enhanced by the doping of g-C3N4, which maintain the effective upconversion luminescence properties even in water, providing a reliable reference for real-time monitoring and feedback of the operating temperature, and further expanding the application fields of photocatalysts. [ABSTRACT FROM AUTHOR]

The problem of water pollution caused by antibiotics urgently needs to be solved urgently. In this study, the Bi5O7I:Er3+-Yb3+ (BOIEY) nanoflowers with a diameter of 600–900 nm loaded flexible fibrous membrane has been synthesized via a combined hydrothermal and electrospinning process. It is noteworthy that the composite fibers successfully achieved efficient catalytic purification under real-time temperature monitoring. The BOIE0.5Y1.5/PAN composite fibers displayed the highest photocatalytic performance in the degradation of tetracycline hydrochloride (TC-HCl), with a removal rate of 91.83% in 80 min, which is 1.76 times that of pure BOI. The efficient photocatalytic performance was mainly attributed to the doping of rare earth ions and the special structure of the composite fibers. Er3+ and Yb3+ ions played the role of broadening the absorption spectrum by upconverting near-infrared light into visible light and promoted the separation of electron and hole pairs, thereby improving the photocatalytic efficiency. In addition, the unique structure of the hollow spherical-flower-loaded flexible fibrous membrane exhibited a larger specific surface area and stronger photon absorption capacity compared with traditional nanocrystals (NCs). Furthermore, based on the 2H11/2/4S3/2 → 4I15/2 radiative transitions of Er3+, the real-time temperature feedback of the degradation process in the 303–433 K ranges is evaluated and the relative temperature sensitivity reaches 0.63% K–1 at 353 K. The dual-function composite fibers provide insight into antibiotic removal in complex environments and ecological restoration. [ABSTRACT FROM AUTHOR]