无机钙钛矿量子点组分对发光特性的影响研究

 2022-07-27 10:07

论文总字数:27183字

摘 要

钙钛矿量子点分为有机-无机杂化物和全无机钙钛矿量子点。有机-无机杂化钙钛矿NH3PbX3(X=I、Br、Cl)对氧和水分比较敏感,稳定性较差。相比于有机-无机杂化钙钛矿材料,全无机钙钛矿表现出了更好的稳定性和更加优异的光学性能。

钙钛矿量子点具有组分调节特性,不同的卤素元素及比例能够合成不同禁带宽度的量子点,这主要是由于不同卤素元素的原子半径不同,从而形成具有不同发光特性的量子点。本研究主要采用热注入(HI)法,在三颈烧瓶中合成CsPbX3 (X=Cl,Br,I)钙钛矿量子点,然后对其进行性能测试,并分析研究钙钛矿量子点的组分调节特性。

首先要制备油酸铯前驱液。然后根据反应方程式以及需要制备的量计算出所需要反应药品的质量,进行CsPbX3钙钛矿量子点的合成实验。由于高温的实验环境,因此在生长量子点时要保持无水无氧状态,将量子点取出时也要快速冷却,以避免量子点被氧化和继续生长成纳米线。制备成功后以紫外可见分光光度计和光纤光谱仪为主要测试仪器来测试和计算量子点的吸光度、半波宽、最大荧光发光峰以及禁带宽度等性能参数,然后调整卤素元素组分,研究其对量子点性能的影响。制备过程中需要不断探索、优化步骤、改变反应条件参数以达到特定需求,得到具有良好光电特性且纯度高的 CsPbX3钙钛矿量子点。

论文通过热注入法来制备量子点及对量子点的性能测试得到以下三个结论:(1)量子点的吸收和光致发光跟量子点组分有关:从CsPbCl3,CsPbBr3到CsPbI3的单一波长钙钛矿量子点,吸收和PL会发生红移;同时,CsPbCl3半波宽最小,色纯度最高。(2)钙钛矿量子点提纯次数越多,PL曲线的峰值会发生明显的红移,但是对吸收影响不大。(3)通过组分调节,量子点发射光谱容易调谐在整个可见光谱区的410-700nm范围。同时CsPbX3量子点的光致发光线宽可以收缩在12−42nm的范围之内,拥有极好的色纯度。

关键词:钙钛矿;量子点;卤化物;组分;荧光特性

Abstract

Perovskite quantum dots are divided into organic-inorganic hybrid and all-inorganic perovskite quantum dots. The organic-inorganic hybrid perovskite NH3PbX3(X=I、Br、Cl) is sensitive to oxygen and water, and its stability is poor. Compared with the organic-inorganic hybrid perovskite, the total inorganic perovskite exhibits better stability and better optical properties.

Perovskite quantum dots have the characteristics of component adjustment. Different halogen elements and ratios can be used to synthesize quantum dots with different bandgap, which mainly depends on the different atomic radii of different halogen elements. Thus, quantum dots with different luminescence properties are formed. In this study, CsPbX3 perovskite quantum dots were synthesized in a three-neck flask by heat injection technique, and the properties of the QDs were tested. First, we prepare the cesium oleate precursor. Then, according to the reaction equation and the amount of preparation to calculate the mass of the drugs needed to react, the synthesis experiment of CsPbX3 perovskite quantum dots was carried out. The absorbance, half-wave width, maximum luminescence peak and band gap of quantum dots were measured and calculated with UV-Vis spectrophotometer and fiber-optic spectrometer, and the halogen composition was adjusted. The effect of QDs on the properties of QDs is studied. In the process of preparation, CsPbx3 perovskite quantum dots with good optoelectronic properties and high purity should be obtained by continuous exploration, optimization steps and changing the parameters of reaction conditions to meet the specific requirements

The following three conclusions are obtained: (1) The absorption and photoluminescence of quantum dots are related to the composition of quantum dots: from the single wavelength perovskite quantum dots from CsPbCl3 to CsPbI3, the absorption and PL have red shift, and the half-wave width of CsPbCl3 is the smallest and has the highest color purity. (2) The higher the purification times of perovskite quantum dots, the obvious red shift will occur in the peak value of the PL curve, but the effect on absorption is not significant. (3) The emission spectra of quantum dots can be easily tuned in the range of 410-700nm in the whole visible spectrum region by adjusting the composition. At the same time, the photoluminescence linewidth of CsPbX3 quantum dots can be narrowed within a narrow range of 12-42 nm, with excellent color purity.

KEY WORDS: perovskite;quantum dot; halide; component; fluorescent characteristic

目 录

摘要 I

Abstract II

第一章 绪论 1

1.1 研究背景及研究意义 1

1.2 钙钛矿量子点的技术发展 1

1.2.1 量子点及其器件的结构和原理 2

1.2.2 量子点的种类及应用 3

1.2.3 无机钙钛矿量子点的研究进展及存在问题 4

1.3 本文研究方法及文章结构安排 5

第二章 量子点性能测试原理 7

2.1 量子点的性能测试 7

2.2 性能测试相关仪器原理 7

2.2.1 紫外可见分光光度计测试原理 7

2.2.2 光纤光谱仪测试原理 8

2.3 本章小结 8

第三章 CsPbX3钙钛矿量子点的制备 9

3.1 CsPbX3钙钛矿量子点的制备原理 9

3.2 制备过程 9

3.2.1 试剂、仪器及药品的称量 9

3.2.2 制备油酸铯前驱液 9

3.2.3 CsPbX3 (X=Cl,Br,或I)量子点的合成 10

3.2.4 CsPbBrxCl3−x和CsPbIxBr3−x量子点的合成 14

3.2.5 量子点溶液沉淀产生原因分析 14

3.3 本章小结 15

第四章 量子点性能测试与分析 16

4.1 CsPbX3钙钛矿量子点性能测试 16

4.1.1 紫外灯照射检测 16

4.1.2 紫外可见分光光度计操作步骤 17

4.1.3 光纤光谱仪操作步骤 18

4.2 CsPbX3钙钛矿量子点性能测试 19

4.2.1 不同颜色的量子点的性能测试 19

4.2.2 不同提纯次数下的量子点性能测试 21

4.2.3 钙钛矿量子点的组分调节 23

4.3 本章小结 24

结论 26

致谢 27

参考文献 28

第一章 绪论

1.1 研究背景及研究意义

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