Efficient energy transfer from self-trapped excitons to Mn^(2+) dopants in CsCdCl_(3):Mn^(2+) perovskite nanocrystals

Mn^(2+)doping has been adopted as an efficient approach to regulating the luminescence properties of halide perovskite nano-crystals(NCs).However,it is still difficult to understand the interplay of Mn^(2+)luminescence and the matrix self-trapped exciton(STE)emission therein.In this study,Mn^(2+)-doped CsCdCl_(3) NCs are prepared by hot injection,in which CsCdCl_(3) is selected because of its unique crystal structure suitable for STE emission.The blue emission at 441 nm of undoped CsCdCl_(3) NCs originates from the defect states in the NCs.Mn^(2+)doping promotes lattice distortion of CsCdCl_(3) and generates bright orange-red light emission at 656 nm.The en-ergy transfer from the STEs of CsCdCl_(3) to the excited levels of the Mn^(2+)ion is confirmed to be a significant factor in achieving efficient luminescence in CsCdCl_(3):Mn^(2+)NCs.This work highlights the crucial role of energy transfer from STEs to Mn^(2+)dopants in Mn^(2+)-doped halide NCs and lays the groundwork for modifying the luminescence of other metal halide perovskite NCs.

Multi-responsive deep-ultraviolet emission in praseodymium-doped phosphors for microbial sterilization

Perusing multimode luminescent materials capable of being activated by diverse excitation sources and realizing multi-responsive emission in a single system remains a challenge.Herein,we utilize a heterovalent substituting strategy to realize multimode deep-ultraviolet(UV)emission in the defect-rich host Li_(2)CaGeO_(4)(LCGO).Specifically,the Pr^(3+)substitution in LCGO is beneficial to activating defect site reconstruction including the generation of cation defects and the decrease of oxygen vacancies.Regulation of different traps in LCGO:Pr^(3+)presents persistent luminescence and photo-stimulated luminescence in a synergetic fashion.Moreover,the up-conversion luminescence appears with the aid of the 4f discrete energy levels of Pr^(3+)ions,wherein incident visible light is partially converted into germicidal deep-UV radiation.The multi-responsive character enables LCGO:Pr^(3+)to response to convenient light sources including X-ray tube,standard UV lamps,blue and near-infrared lasers.Thus,a dual-mode optical conversion strategy for inactivating bacteria is fabricated,and this multi-responsive deep-UV emitter offers new insights into developing UV light sources for sterilization applications.Heterovalent substituting in trap-mediated host lattice also provides a methodological basis for the construction of multi-mode luminescent materials.

Physically-based enhancement in shallow water resimulation

To resimulate a customized fluid derived product by analyzing an existing fluid is significant and difficult.This paper proposes a driven model recovery method,which is challenging in fluid resimulation customization.First,fluid physical properties are calculated under the constraints of appearance and dynamic behavior of the example water.Second,a hybrid particle lattice Boltzmann method for shallow water(LBMSW)is recovered from the dynamic geometry on fluid surface.As it is found that the resimulation details fade gradually with LBMSW auto-advection,a physically-based enhancement scheme is presented.A nonlinear algorithm is introduced to stretch the faded density to retain resimulation details.Experiments show that the proposed approach can obtain more realistic resimulation products in several challenging scenarios.