Research On The Stability And Luminescence Properties Of All-Inorganic Perovskite Nanocrystals And Oxides Composite Structure

The development of semiconductor display technology urgently needs to vigorously promote the research on high-efficiency,high-quality,multi-function display materials.All-inorganic halide perovskite nanocrystals（NCs）have become the most promising display materials due to their advantages of high fluorescence quantum efficiency,tunable emission spectrum,high defect tolerance and good monochromaticity.However,its poor chemical stability,severe self-absorption of photons in solid-state display applications,differences in color rendering of solid solution components and cumbersome synthesis methods limit its application in high-quality display fields.In response to the above problems,this paper has carried out the research of the following work content:（1）Ultra-small Cs Pb Br₃（CPB）nanocrystals have been synthesized by mesoporous microreaction in-situ growth,Mesoporous silicon oxide（m-Si O₂）have ordered pore structure and Cs Pb Br₃ nanocrystals can grow efficiently and rapidly,which can improve the chemical stability through the link between the NCs and network pore structure.Secondly,using micro-reactor mesoporous structure to effectively isolate NCs to reduce self-absorption and improve their photon efficiency.In addition,photons from nanocrystals can effectively be transmitted due to the channel of m-Si O₂,meanwhile,m-Si O₂ has lower refractive index and higher transmittance,which effectively reduces the loss of NCs light emission inside the mesopores,and its emission is improved by 44.7% compared with the quantum dots without m-Si O₂ protection.Simultaneously,continuous working performance of flexible display devices made of Cs Pb Br₃/m-Si O₂（CPB/MS）composite materials has been significantly improved.（2）Cs Pb X₃ nanocrystals powder with excellent optical properties can be obtained by mechanochemical method at room temperature without inert gas in 15 min,whose spectral range can cover the 408-682 nm.Meanwhile,Cs₃Sb₂Cl₉,Cs₃Sb₂Br₉ nanocrystals,Cs Pb Br₃/Ti O₂ heterojunction,Eu³⁺,Mn²⁺ doped Cs Pb X₃ nanocrystals and their flexible fluorescent films are also obtained.In addition,the quantum yield of the Cs Pb Br₃/Ti O₂ heterojunction is increased by 56.9% compared to the Cs Pb Br₃ nanocrystal and thermal stability improved by 2.8 times.