【作者】 张杰；

【导师】 周贤菊；

【作者基本信息】 重庆邮电大学 ， 集成电路工程（专业学位）， 2022， 硕士

【摘要】 钙钛矿量子点作为一种新型发光材料,它具有发射光谱可调控、色纯度高、荧光量子产率高、载流子扩散距离长等优点,可以应用到太阳能电池、激光器、液晶显示器、发光二极管等领域。但是,钙钛矿量子点目前存在很多问题,如铅离子毒性问题、量子点团聚问题等。针对这些问题,本文具体做了以下研究:（1）针对配体引起的团聚现象,本文选取四种不同碳链酸类配体正辛酸（C8）、月桂酸（C12）、二-己基葵酸（C16）、油酸（C18）制备CsPbBr₃量子点。通过XRD衍射峰和形貌测试得出,它们的形貌相似且均成立方晶相。对比四种材料的光稳定性、热稳定性和空气稳定性,发现均是C16量子点稳定性最好,说明它能有效改善量子点团聚问题,提升其稳定性能。本文最后验证了这四种钙钛矿量子点制备的发光二极管（LEDs）均可发出强烈绿光,为提升绿光LEDs器件性能开辟了更多道路。（2）为了进一步提升钙钛矿量子点稳定性,本文选取三正辛基膦（TOP）、三正辛基氧膦（TOPO）和双十二烷基二甲基溴化铵（DDAB）三种修饰配体分别对CsPbBr₃量子点进行表面修饰。通过XRD衍射峰和形貌测试得出,它们的形貌分布均匀且均成立方晶相。对比它们的光稳定性和热稳定性,发现DDAB修饰后的CsPbBr₃量子点稳定性最佳。在365 nm紫外光下持续照射四十天后DDAB修饰后的CsPbBr₃量子点仍能发出强烈绿光,在与水混合（4:1）四十天后也能发出强烈绿光,说明DDAB修饰配体有效稳定了CsPbBr₃量子点晶体结构,减少了材料表面缺陷。最后,用DDAB修饰后的CsPbBr₃量子点制备了LEDs器件,测试结果显示,在不同驱动电压下LEDs器件的电致发光光谱非常稳定,且色坐标变化极小,说明器件的稳定性好、色纯度高。（3）本文对醋酸甲脒（FA⁺）和锰离子(Mn²⁺)共掺杂Cs Pb Cl₃量子点进行了深入研究,通过XRD衍射峰和形貌测试得出Mn²⁺离子成功替代了部分Pb²⁺离子,FA⁺离子成功替代了部分Cs⁺离子。将Cs Pb Cl₃:FA⁺,Mn²⁺量子点与Cs Pb Cl₃:Mn²⁺量子点对比得出,在25-70℃范围内激子发光中心的热稳定性从17%提升到了32%,Mn²⁺离子发光中心的热稳定性从60%提升到了97%;且Cs Pb Cl₃:FA⁺,Mn²⁺量子点经过六次热循环测试后,在初始温度下激子发射光谱强度能恢复到初始值的81%,Mn²⁺离子发射光谱强度能恢复到初始值的97%,说明FA⁺,Mn²⁺离子共掺杂不仅降低了Pb²⁺离子毒性问题,还极大提升了热稳定性和热循环性。最后,将Cs Pb Cl₃:FA⁺,Mn²⁺量子点封装白光LEDs器件,在40 m A驱动电流下的色坐标为（0.3367,0.3506）,相关色温为5745 K,显色指数为88.2,具有白光LEDs应用潜力。更多还原

【Abstract】 As a new type of light-emitting material,perovskite quantum dot has the advantages of controllable emission spectrum,high color purity,high fluorescence quantum yield,long carrier diffusion distance,and can be applied to solar cells,lasers,liquid crystal display,light-emitting diode and other fields.However,there are many problems in perovskite quantum dots,such as lead ion toxicity problem,quantum dot agglomeration problem and so on.In view of these problems,this paper specifically does the following specific research:（1）For the agglomeration phenomenon caused by ligands,four different ligand ligands orthopoic acid（C8）,lauric acid（C12）,di-hexanemic acid（C16）and oleic acid（C18）were selected to prepare CsPbBr₃quantum dots.The XRD diffraction peak and morphology tests are similar and all form square crystal phase.Comparing the optical stability,thermal stability and air stability of the four materials,it is found that the C16quantum dot has the best stability,indicating that it can effectively improve the quantum dot agglomeration problem and improve its stability energy.In this paper,the light-emitting diodes（LEDs）prepared by these four perovskite quantum dots can emit strong green light,which opens up more ways to improve the performance of green LEDs devices.（2）In order to further improve the stability of perovskite quantum dots,this paper selected tri-n-octylphosphine（TOP）,trioctylphosphine oxide（TOPO）and didodecyldimethylammonium bromide（DDAB）for surface modification of CsPbBr₃quantum dot.The XRD diffraction peak and morphology test showed uniform morphology distribution and square crystal phase.Contrasting their optical and thermal stability reveals the best CsPbBr₃quantum dot stability after DDAB modification.DDAB modified CsPbBr₃quantum dots after 40 days of 365 nm UV light can still emit strong green light and strong green light after mixing with water（4:1）,indicating that DDAB modified ligands effectively stabilize the crystal structure of CsPbBr₃quantum dots and reduce material surface defects.Finally,LEDs devices were prepared with CsPbBr₃quantum dots modified with DDAB.The test results showed that the electroluminescence spectrum of LEDs devices is very stable under different driving voltages,and the color coordinate change is very small,indicating that the device has good stability and high color purity.（3）In this paper,the co-doping Cs Pb Cl₃quantum dots of methamidine acetate（FA⁺）and manganese ion(Mn²⁺)were deeply studied.The XRD diffraction peak and morphology test showed that Mn²⁺ion successfully replaced part of Pb²⁺ion,and FA⁺ion successfully replaced part of Cs⁺ion.Then,by comparing Cs Pb Cl₃:FA⁺,Mn²⁺quantum dot with Cs Pb Cl₃:Mn²⁺quantum dot,we showed that the thermal stability of exciton luminescence center in the 25-70℃range increased from 17%to 32%,and the thermal stability of Mn²⁺ion luminescence center increased from 60%to 97%.After Cs Pb Cl₃:FA⁺,Mn²⁺quantum dots,the exciton emission spectral intensity to 81%of the initial value and Mn²⁺ion emission spectral intensity to 97%of the initial temperature,indicating that FA⁺and Mn²⁺ion co-doping not only reduces the Pb²⁺ion toxicity,but also greatly improves the thermal stability and thermal cyclability.Finally,the Cs Pb Cl₃:FA⁺,Mn²⁺quantum dot package the white light LEDs device,the color coordinate at40m A driving current is（0.3367,0.3506）,the relevant color temperature is 5745 K,the color development index is 88.2,has the application potential of white light LEDs.更多还原