MOF-2的水相合成及其热稳定和介电性能研究  

Thermal Stability and Dielectric Relaxation of MOF-2 Synthesized in Aqueous Phase

作　　者：程蕾 闫普选[3] 杜博豪[3] 叶思 邹华红 CHENG Lei;YAN Puxuan;DU Bohao;YE Si;ZOU Huahong(School of Chemistry and Pharmaceutical Science,Guangxi Normal University,Guilin Guangxi 541004,China;Guangxi Key Laboratory of Low Carbon Energy Materials(Guangxi Normal University),Guilin Guangxi 541004,China;School of Materials Science and Engineering,Guilin University of Electronic Technology,Guilin Guangxi 541004,China)

机构地区：[1]广西师范大学化学与药学学院,广西桂林541004 [2]广西低碳能源材料重点实验室(广西师范大学),广西桂林541004 [3]桂林电子科技大学材料科学与工程学院,广西桂林541004

出　　处：《广西师范大学学报（自然科学版）》2023年第5期86-95,共10页Journal of Guangxi Normal University:Natural Science Edition

基　　金：广西自然科学基金(2020GXNSFBA297001);广东省基础与应用基础研究基金-粤桂联合基金(2021A1515410006)。

摘　　要：金属有机框架材料(metal-organic frameworks,MOFs)作为超低介电层间介质(ILD)材料,在满足高端芯片等微电子器件的大规模集成化发展方面显现出巨大的应用潜力。本文在常温常压水相中制备结晶性良好的MOF-2晶体,采用Rietveld精修分析MOF-2晶体的晶胞参数;研究MOF-2晶体在受热脱水过程中结构的变化,发现分子结构发生重排生成[Zn(BDC)(DMF)]和[Zn(BDC)(H_(2)O)]_(2)种结构,100℃加热6 h后,这2种产物的物相占比分别为89%和11%;采用介电频谱研究其介电性能,发现水相制备的MOF-2介电常数随频率变化较大,高频时相对介电常数稳定在4~5(>1 MHz),中频、低频时表现出较大的介电响应,这主要是由水分子和DMF的协同作用产生,受热脱去部分溶剂分子后产物的相对介电常数不再随频率发生变化并保持在约3.39(0.1~1 MHz);MOF-2脱去所有溶剂分子后生成片状结构的[Zn(BDC)],相对介电常数为3.91(0.1~1 MHz)。基于介电弛豫理论分析,MOF-2的介电响应主要由低频的直流电导、中频时水分子和DMF的协同极化作用、高频时的电子/离子位移极化以及普适介电响应(UDR)等4方面的弛豫机制贡献。本研究阐明了水相合成MOF-2及其受热脱溶剂产物的结构特征、介电性能和极化弛豫机制,为MOF-2在电学领域的应用提供了理论依据。As ultra-low dielectric layer dielectric(ILD)materials,metal-organic frameworks(MOFs)show great application potential in the development of large-scale integrated circuit for high-end chips and other microelectronic devices.In this paper,MOF-2 with good crystallinity was prepared in the aqueous phase at room temperature and pressure,and the lattice parameters were analyzed by Rietveld refinement.Because of molecular structure rearrangement,the crystal structure of MOF-2 was changed into two desolvent products with[Zn(BDC)(DMF)]and[Zn(BDC)(H_(2) O)]during thermal dehydration.After heating at 100℃for 6 h,the phases of these two products were 89%and 11%respectively.The dielectric properties of the products were studied by using dielectric spectrum.It was found that the dielectric constant of MOF-2 prepared in aqueous phase changed greatly with frequency,and the relative dielectric constant was 4-5 above 1 MHz.The synergistic effect of water and DMF molecule had a major impact on the dielectric response of MOF-2 at mid and low frequency.The relative dielectric constant of the product no longer changes with the frequency after heating and remains at about 3.39(0.1-1 MHz).After removing all solvent molecules,MOF-2 generates[Zn(BDC)]with sheet structure,and the relative dielectric constant is 3.91(0.1-1 MHz).Based on the dielectric relaxation theory,the dielectric response of MOF-2 could be described by four relaxation mechanisms:dc conductivity in low frequency,synergistic polarization of water molecules and DMF in intermediate frequency,electron/ion displacement polarization in high frequency,and the universal dielectric response(UDR).This study clarified the structural characteristics,dielectric properties and polarization relaxation mechanism of MOF-2 synthesized in aqueous phase and its desolvent products,the result provided a theoretical basis for the application of MOF-2 in the electrical field.

关 键 词：MOF-2 晶体结构 介电性能 热稳定性 极化弛豫 

分 类 号：O641[理学—物理化学] O76[理学—化学]