Synthesis and luminescence of ultrasmall CsPbBr_(3) nanocrystals and CsPbBr_(3)/Cs_(4)PbBr_(6) composites by one-pot method

All-inorganic perovskites CsPbX_(3)(X=Cl,Br,I)have attracted worldwide interest due to their excellent lumi-nescent performances.Meanwhile,Cs_(4)PbBr_(6) have been studied because they can enhance the luminescent efficiency and stability of CsPbBr_(3).Herein,we introduced a microfluidic method based on room-temperature supersat-urated recrystallization to synthesize blue-emitting CsPbBr_(3)nanocrystals(NCs)and green-emitting CsPbBr_(3)/Cs_(4)PbBr_(6)NCs.The ultrasmall CsPbBr_(3)NCs emitted at a deep blue wavelength of 461 nm with the full width at half maximum(FWHM)of 15 nm.transmission electron microscopy(TEM)results demonstrated that ultrasmall CsPbBr_(3)NCs with the average particle size of 3.8 nm were synthesized and the CsPbBr_(3)NCs were crystallized as monoclinic structure.

Flexible Strip Supercapacitors for Future Energy Storage

Flexible strip supercapacitors are developed and their electrochemical properties are characterized. Activated carbon is used as the electrode material and it is found to have a good porous structure which provides a large surface area for energy storage.Furthermore, this activated carbon performs well. The manufacturing processes for the supercapacitors are described in detail and the preparation process has good reproducibility. The strip supercapacitors are combined in series and parallel to measure their electrical properties. The performances of these two samples in series or in parallel both follow the theoretical models. The electrochemical potential window of a series circuit of these two strip supercapacitors is 4.8 V. The energy and power of the series or parallel circuits are equal to the sums of the two strip supercapacitors.

A strategy to achieve efficient green-emission dual-mode luminescence of Yb^(3+),Er^(3+) doped NaBiF_(4)

A series of hexagonal phase NaBiF_(4):x Yb^(3+),y Er^(3+) were successfully synthesized by solvothermal method.The morphology,phase structure,up-conversion luminescence and down-conversion luminescence properties of Yb^(3+) and Er^(3+) doping concentration and the energy transfer mechanism were studied.It shows that the doping of Yb^(3+) and Er^(3+) does not cause the phase transition of NaBiF_(4),but influences its morphology.In the NaBiF_(4):Yb^(3+),Er^(3+),Yb^(3+) can transfer energy with Er^(3+),enhancing up-conversion green emission.With Yb^(3+) doping concentration increasing,the up-conversion red-green ratio will increase while the down-conversion intensity of the green emission decreases and that of the red emission increases.Considering the potential application of Na BiF4:x Yb^(3+),y Er^(3+) phosphors in optical illumination,the thermal stability was carried out.