【作者】 王韬；

【导师】 崔得良； 刘陟；

【作者基本信息】 山东大学 ， 材料物理与化学， 2010， 硕士

【摘要】 在有机-无机复合材料中,通过调控有机-无机界面可以实现两种组分的优势互补,从而得到具有优良综合性能的材料,因此有机-无机复合材料日益受到重视。对有机-无机复合半导体材料来讲,它的稳定性又是决定半导体器件寿命和可靠性的关键参数,为此,我们利用原位红外光谱,跟踪研究了一类新型层状类钙钛矿有机-无机复合半导体晶体材料((4-X-C6H4-NH3)3[CdBr5],X=Cl,Br)的热稳定性。为了更准确地解释实验结果,我们首先利用高斯软件(DFT／B3LYP／6-31G(d))对晶体的气态分解产物(4-X-C6H4-NH2,X=Cl,Br)和晶体中的有机阳离子(4-Cl-C6H4-NH3+)的红外光谱进行了计算,得到了与实测红外光谱比较吻合的结果,为相关特征吸收峰的归属提供了依据。对复合晶体进行的热分析显示,上述复合晶体的分解温度为178～210℃,而且分解后残余固态产物为CdBr2。红外漫反射原位监测结果表明,样品分解前与氢键相关的铵根吸收峰等发生峰位转移、峰强度减弱等现象；样品开始分解后,气态产物4-X-C6H4-NH2和HBr从晶体中脱除,并在较低温度下重新结合成有机铵盐。当利用高纯氮气在晶体上施加一定的压力时,晶体的分解温度随压力的提高有较大幅度的提高。这个结果提示,施加压力有利于提高该晶体材料的热稳定性。更多还原

【Abstract】 Due to the possibility of combining the merits of both organic and inorganic components, organic/inorganic hybrid materials have attracted much attention. Researchers have carried out intensive and extensive investigations on the preparation and properties of organic/inorganic hybrid materials, in order to prepare materials with excellent properties. From the view of practical applications, the thermal stability is a key factor to the hybrid semiconductors, because it determines the reliability and durability of the electronic devices. In this thesis, we investigated the thermal stability of a new layerd perovskite-like organic/inorganic hybrid semiconducting crystals ((4-X-C6H4-NH3)3CdBr5, X=Cl, Br) by an in-situ FTIR technique, and the effect of pressure on the thermal decomposition of these crystals were also studied.For clearly explaining the experimental results, we calculated the IR absorption spectra of (4-X-C6H4-NH2, X=Cl, Br) and (4-Cl-C6H4-NH3+) using the Gaussian software (DFT/B3LYP/6-31G(d)). The result indicates that, the computational spectra agreed quite well with that collected in the experiments.The thermal analysis results revealed that, the decomposition temperature of ((4-X-C6H4-NH3)3CdBr5, X=Cl, Br) was 178-210℃, and the remaining solid after complete decomposition was CdBr2. Furthermore, the results of FTIR in-situ monitoring experiments indicated that, the IR peaks of-NH3 which related to the hydrogen bonds red-shifted or weakened before the decomposition process started. With the temperature exceeding the decomposition point, gaseous products 4-X-C6H4-NH2 and HBr escaped from the crystals, and they recombined into organic ammonia salt at the place with lower temperature. On the other hand, the decomposition temperature of the crystals increased to a rather large extent when a pressure of-4MPa was applied on them. This phenomenon proved that, the thermal stability of the hybrid crystals can be improved by applying a high pressure.更多还原