形貌可控的CsPbBr_(3)钙钛矿纳米晶的制备及其形成动力学的原位光致发光研究  

Preparation of CsPbBr_(3) perovskite nanocrystals with controllable morphology and in-situ photoluminescence of formation kinetics

作　　者：陈雪莲 巨博 焦琥珀 李燕 钟玉洁 Chen Xue-Lian;Ju Bo;Jiao Hu-Po;Li Yan;Zhong Yu-Jie(School of Materials Science and Engineering,Xi’an Shiyou University,Xi’an 710065,China)

机构地区：[1]西安石油大学材料科学与工程学院,西安710065

出　　处：《物理学报》2022年第9期273-281,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62104191);陕西省重点研发计划(批准号:2021GY-133);西安交通大学金属材料强度国家重点实验室和西安石油大学研究生创新与实践能力培养计划(批准号:YCS19212058)资助的课题。

摘　　要：通过添加不同比例的十二烷二酸(DDDA)配体,在室温下采用配体辅助再沉淀法制备CsPbBr_(3)钙钛矿纳米晶.利用X射线衍射仪、透射电子显微镜、紫外分光光度计、荧光光谱仪等对纳米晶的相结构、微结构和光学性质进行了表征.结果显示:所有纳米晶产物均为立方相结构;而纳米晶形貌会随着DDDA浓度的增加从纳米立方块逐渐转变为厚度均一的纳米片,同时光致发光光谱从绿光区移至蓝光区.结合实验室搭建的具有超高时间分辨率(约100 ms)的原位光致发光装置,实时监测了不同形貌纳米晶在形成过程中光致发光光谱的演变.结果表明:未使用DDDA时前驱体经历了快速成核和尺寸分布聚焦生长后生成纳米立方块;DDDA的出现促进了纳米晶在形成早期生成各向异性的纳米片,然而随着反应时间的延长,具有不对称结构的纳米片会通过溶解-再结晶方式转变为热力学稳定的纳米立方块.本工作对形貌可控的钙钛矿纳米晶的精准合成具有一定参考价值.Cesium-lead halide perovskite nanocrystals(CsPbBr_(3)(X=Br,Cl,I)PNCs)have become ideal luminescent materials for wide color gamut display devices,white LED lighting and high-efficiency solar cells,due to adjustable energy band gap,high fluorescence quantum yield,narrow fluorescence emission peak,and ultra-high defect tolerance.The preparation of CsPbBr_(3)PNCs with controllable size and morphology is a prerequisite for obtaining efficient and stable photovoltaic/photovoltaic devices.In this report,the CsPbBr;PNCs with different shapes are prepared by adding different concentrations of dodecanedioic acid(DDDA)ligands at room temperature through using ligand-assisted reprecipitation method.Utilizing the X-ray diffractometer,transmission electron microscopy,ultraviolet spectrophotometer,fluorescence spectrometers(PL),the phase structure,microstructure and optical properties of the nanocrystals are investigated.The results show that the presence of DDDA ligands have no influence on the phase structure of nanocrystal products,they all present a cubic phase structure.Surprisingly,the morphology of the nano crystals gradually transforms from nano cubes into nanoplatelets with~5 layers in thickness as the concentration of DDDA increases.In addition,the PL spectrum shows a significant blue shift from 509 nm to 478 nm.By using the in-situ homemade PL device with ultra-high time resolution(~100 ms),the real-time monitoring PL spectra of nanocrystals in the formation process are measured.The results demonstrate that nanocrystals undergo rapid nucleation and focusing of size distribution growth to generate nanocubes in the absence of DDDA ligand.When the DDDA ligand is present,nanocrystals are mainly nanoplatelets in the early growth stage due to the decelerated reaction.As the reaction proceeds,nanocubes can emerge and grow gradually while the nanoplatelets disappear when the concentrations of DDDA ligands are 25%and 50%.As the concentration is further increased to 75%,almost nanoplatelets could be formed after the nucleatio

关 键 词：钙钛矿纳米晶 形貌转变 原位光致发光 生长动力学 

分 类 号：TB383.1[一般工业技术—材料科学与工程]