Study On Luminescent Composites Of Perovskite Quantum Dots And Porous Glass And Its Devices

Recently developed CsPbX₃?X=Cl,Br,and I?perovskite quantum dots?QDs?have attracted enormous attention in optoelectronics because of their remarkable optoelectronic properties including high quantum yield of luminescence,narrow emission line width,and tunable emissions.Unfortunately,the poor stability of CsPbX₃ quantum dots?QDs?under water,high temperature and light irradiation conditions still remains an issue in their application.Moreover,the halide ions in one CsPbX₃ QDs could exchange with another type of halide ions in nearby QDs in LED devices.All these disadvantages of CsPbX₃ QDs hinder their application in LED,display,and so on.In this paper,we intended to use composite nano-porous glass?NPG?transparent materials with CsPbX₃ QDs,which nano-pores could protect CsPbX₃ QDs from water.The ions in NPG channel could reconstruct the surface of CsPbX₃ QDs and enhance the stability of CsPbX₃ QDs.In addition,the composite materials could apply to anti-counterfeiting or environment as a water responsive material according the reversibility of surface reconstruction.The CsPbX₃ composited NPG transparent materials were prepared through a solution impregnation method.These novel composite materials exhibit intense and shining emission,and are capable of switching colors upon successive stimuli of deionized water and nonaqueous solutions containing bromine ions.An in-situ confocal microscope dynamically demonstrates the responsive behavior.Additionally,the bulk composite materials could still give a switched bluish emission even after a duration of several months in water.It is found that the residual chloride ions in the nano-sized pores of NPG,which are introduced in the preparation of the blank NPG,play a significant role in stimuli responsive behaviors and long-term resistance to water.These results indicate the surface modification of CsPbX₃ QDs by ions in the pore of porous glass.This research offers a perspective for fabricating stimuli responsive materials with the ion-exchangeable perovskite QDs.In addition,we have successfully prepared CsPbX₃/NPG powder materials by solution impregnation method.Herein,we assemble WLEDs by mixing as-prepared CsPbBr₃/NPG powder and CsPb(Br_0.4I_0.6)₃/NPG powder transparent materials in silicone resin and placing them on a blue InGaN LED chip.It is indicated that the existence of NPG in solid-state LEDs effectively weakens the decay of red emission by light and thermal generated from LED.We fabricate a WLED by combining a blue InGaN LED with as-prepared CsPbBr₃/NPG powder and KSF as green and red phosphors,respectively.The WLED exhibit better luminescence stability,which luminous efficiency and correlated color temperature are 77 lm/W and4173 K,respectively.It is found that the pores of porous glass have protective effect on CsPbX₃ QDs under light-irradiation and thermal condition,which slows the decay of CsPbX₃QDs in LED.This research makes the CsPbBr₃/NPG powder composites potentially interesting for application in lighting and displays.