Inspired by the anti‐freezing mechanisms found in nature, ionic compounds (ZnCl2/CaCl2) are integrated into cellulose hydrogel networks to enhance the freezing resistance. In this work, cotton cellulose is dissolved by a specially designed ZnCl2/CaCl2 system, which endows the cellulose hydrogels specific properties such as excellent freeze‐tolerance, good ion conductivity, and superior thermal reversibility. Interestingly, the rate of cellulose coagulation could be promoted by the addition of extra water or glycerol. This new type of cellulose‐based hydrogel may be suitable for the construction of flexible devices used at temperature as low as −70 °C.

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Ba 1.8−x Sr x SiO 4 :0.1Ce 3+ ,0.1Na + (x = 0−1.8) phosphors were prepared by a high-temperature solid-state reaction. The emission peaks of Ba 1.8−x Sr x SiO 4 :0.1Ce 3+ ,0.1Na + shift from 391 to 411 nm with increasing Sr 2+ content under excitation by a UV light at around 360 nm. Ba 0.4 Sr 1.4 SiO 4 :0.1Ce 3+ ,0.1Na + phosphor exhibits the best performance of luminescence, whose absolute quantum efficiency is 97.2%, and the emission intensity at 150 °C remains 90% of that at room temperature. The effect of replacing Ba 2+ by Sr 2+ on the red shift of the emission band and the increase of quantum efficiency (QE) and thermal stability (TS) was investigated in detail based on the Rietveld refinements, Raman spectra, thermoluminescence, and decay curves, etc. The performance of UV chip-based pc-LEDs indicates that Ba 0.4 Sr 1.4 SiO 4 :0.1Ce 3+ ,0.1Na + can be a promising blue phosphor for white-emitting pc-LEDs.

Photoluminescence quantum efficiency (QE) and thermal stability are important for phosphors used in phosphor-converted light-emitting diodes (pc-LEDs). LiSrCa(SiO):0.03Ce (-0.7 ≤ x ≤ 1.0) phosphors were designed from the initial model of LiSrCa(SiO):Ce, and their single-phased crystal structures were found to be located in the composition range of -0.4 ≤ x ≤ 0.7. Depending on the substitution of Sr for Ca ions, the absolute QE value of blue-emitting composition-optimized LiSrCa(SiO):0.03Ce reaches ∼94%, and the emission intensity at 200 °C remains 95% of that at room temperature. Rietveld refinements and Raman spectral analyses suggest the increase of crystal rigidity, increase of force constant in CeO, and decrease of vibrational frequency by increasing Sr content, which are responsible for the enhanced quantum efficiency and thermal stability. The present study points to a new strategy for future development of the pc-LEDs phosphors based on local structures correlation via composition screening.

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