In Situ Growth And Optical Properties Of CsPbBr₃ Perovskite Quantum Dots In Glass

The all-inorganic perovskite CsPbBr₃ QDs has potential applications in light-emitting diodes,solar cells,lasers and photodetectors due to its advantages of high photoluminescence quantum yield(PLQY),narrow emission,high defect tolerance and easy synthesis.However,the instability and large-scale synthesis of all-inorganic perovskites are still the main obstacles that limit their practical applications.Furthermore,the high density and uniform composition make QDs not be eroded by the surrounding environment.Meanwhile,glass ceramics can prevent QDs particles from aggregating or dissolving and it is easy to control the size and distribution of QDs embedded glass ceramics relatively.However,the PLQY of Cspb Br₃ QDs prepared in glass is still low,and there are few studies on the growth regulation of QDs by glass components and the growth kinetics of QDs in glass matrix.Therefore,in this paper,CsPbBr₃ QDs are grown in situ in borosilicate glass with a low melting temperature,and the QDs are protected by transparent inert glass.The growth and degradation processes of CsPbBr₃ QDs on glass substrates were studied by in-situ TEM,and their luminous efficiency,improved transparency and controllable adjustment of the spectra were achieved through rare earth doping strategies and glass structure design.In addition,its potential applications in short-wavelength shielding and backlight display are discussed.1.Here,we employ a glassy matrix to produce CsPbBr₃ QDs to ensure that the growth and degradation processes of CsPbBr₃ QDs are recorded in the vacuum chamber, which could avoid the influence of the external factors,under electron beam(E-beam)irradiation.In addition,two stages of degradation pathways induced by the E-beam are observed sequentially:(1)a layer-by-layer decomposition and(2) instantaneous vanishing once the radius reaches the critical radius(².3 nm). Indeed,we demonstrated that defects serve as a key flash point that could trigger the structural collapse of CsPbBr₃ QDs.2.It is explored that the adjustment of glass topology can realize a simple and effective self-crystallization method to precipitate CsPbBr₃ QDs in borosilicate glass.We proved that Pb²⁺as a network outer body has a large ionic potential energy,which leads to a large free energy of the system,so that spontaneous phase separation occurs in the glass grid structure and promotes the nucleation and crystallization of CsPbBr₃ QDs in the glass.Impressively,the CsPbBr₃ QDs@glass exhibited exceptional thermal stability,photo-stability,and water resistance.The on-chip w LEDs were constructed by coupling green and red CsPbX₃@glass powders with a commercial blue GaN chip.3.The PLQY and visible light transmittance of CsPbBr₃ QDs glass can be significantly improved by doping with different Eu³⁺concentrations.Through a series of characterization methods,it is proved that Eu³⁺plays a role of nucleating agent in the growth process of CsPbBr₃ QDs.In addition,Eu³⁺doped CsPbBr₃ glass-ceramics has excellent short wavelength shielding capability,even in 480 h accelerated weathering tests showed good shielding performance.