Research On The Luminescence Stability Of CsPbBr₃ Quantum Dots And The Performance Of QLED

All-inorganic lead halide perovskite quantum dots have received widespread attention in the field of optoelectronic devices due to their tunable band gap,high carrier mobility,and extremely narrow half-width.However,its ionic structural properties and easy reaction in the external environment result in unstable luminescence properties of the lead halide perovskite,which limits its application.In this paper,the phase composition and regulation of CsPbBr₃ quantum dots are realized by changing the synthesis conditions of the lead perovskite halide luminescence material used in QLED devices,the correlation mechanism between the composition of the crystal phase and the luminescence performance is evaluated,and the stability of the device under the NiO hole transmission of QLED devices is discussed.The details are as follows:In the process of synthesizing,the CsPbBr₃ quantum dots are synthesized by thermal injection method.The crystal phase composition of CsPbBr₃ nanocrystals is adjusted by adjusting the ratio of OA and OAM to realize the transition from CsPbBr₃ phase to CsPbBr₃/Cs₄Pb Br₆ phase.The luminescence properties of CsPbBr₃/Cs₄Pb Br₆ quantum dots are improved by adding 1,9-DN in the precursor because the introduction of Br reduce the density of Br vacancy defects.On the basis of effectively reducing Br defects and regulating the composition of the mixed phase of CsPbBr₃ quantum dots,the luminescence stability of quantum dot materials in light irradiation,aqueous solutions,high temperatures and polar solvents was analyzed.It was found that luminescence stability compared with not adding 1,9-DN,the CsPbBr₃/Cs₄Pb Br₆ mixed crystal phase quantum dots prepared by adding 1,9-DN have significantly improved in the environment.With NiO_x used as the hole function layer,a device with a structure of ITO/NiOx/PVK/QDs/TPBi/Li F/Al is fabricated.Under annealed in an oxygen atmosphere,the roughness of NiO_xfilm is reduced,meanwhile,the hole carrier concentration is improved.EL spectrum test shows that the maximum EL luminous intensity reaches to 2′10⁶,and the stability of QLED is also improved accordingly.