有机聚合物PEDOT热输运机理及性能调控的理论研究

Poly(3,4-ethylenedioxythiophene) (PEDOT), a high performance of organic polymer thermoelectric materials, has received great attention from experimenters. Very recent experimental studies show that the thermoelectric properties of PEDOT have been greatly improved after appropriate treatment. However, the unclear heat transport mechanism and the lack of thermal performance regulation means seriously restrict further enhance the thermoelectric properties of PEDOT. This project intents to carry out in-depth investigation on the thermal properties of PEDOT by density functional theory combines with Boltzmann transport equation, the main work includes: (i) investigate the intrinsic thermal properties of PEDOT, analysis the root causes of difference thermal conductivity in all directions; (ii) reveal the influence of strain and doping on the thermal properties of PEDOT and give its internal mechanism by phonon spectrum and density of states; (iii) explore the thermal transport properties of low-dimensional PEDOT and clarify its mechanism of action on phonon transport. This project can achieve in-depth understanding the thermal transport mechanism in PEDOT which is urgent need to understand in experiments, get the knowledge on how to regulate the thermal conductivity of PEDOT, which provide important theoretical basis and ideas on exploring high-performance organic conductive polymer thermoelectric materials in experiments.

Poly 3,4-ethylenedioxythiophene (PEDOT)作为一种性能优异的有机聚合物热电材料而得到广大实验人员的关注，近期的实验研究发现经过适当处理后PEDOT的热电性能得到很大提高。然而，该体系热输运机理的不明晰、调控热学性能手段的缺乏严重制约着热电性能的进一步提升。本项目拟采用密度泛函理论与玻尔兹曼输运方程相结合的方法研究PEDOT的热学性质，主要工作包括：(1)、深入研究PEDOT的本征热学性质，分析各个方向上热导率差异的根源；(2)、揭示不同应变、掺杂对PEDOT热学输运性质的影响，通过声子谱及态密度分析其内在机理；(3)、探索低维化的PEDOT中的热学输运性质，阐明其对声子输运的作用机制。本项目的开展可以揭示实验上急需了解的PEDOT热学输运机制，明确调控该体系热导率的方式，为实验上更好地开发基于有机导电聚合物热电材料提供重要的理论依据和思路。

Poly 3,4-ethylenedioxythiophene (PEDOT)作为一种性能优异的有机聚合物热电材料而得到广大实验人员的关注，近期的实验研究发现经过适当处理后PEDOT的热电性能得到很大提高。然而，该体系热输运机理的不明晰、调控热学性能手段的缺乏严重制约着热电性能的进一步提升。本项目采用密度泛函理论与玻尔兹曼输运方程相结合的方法研究了PEDOT的本征热学性质。在本项目的支持下，完成了基于有机聚合物热电材料PEDOT 模型的构建，并利用密度泛函理论按能量最低原理确定了材料的最稳定构型，并在此基础上研究了PEDOT的本征热学性质。在声子谱的研究分析中发现PEDOT中始终存在大量声子虚频，预示着最稳定构型在热扰动情况下不再稳定，且存在不可忽略的范德瓦耳斯力相互作用，对体系进行范德瓦尔斯力修正后发现，声子谱中仍旧存在虚频，表明热扰动导致的结构不稳定，非常容易发生大的结构扭曲，这点也与实验结果很吻合，实验合成的PEDOT呈现非常复杂的空间扭曲结构。我们也分别研究了石墨烯纳米带-DNA分子结的电热输运性能及其应用；腺嘌呤和卟啉分子的热电性能；石墨炔及类石墨炔碳氮化物纳米带中的电子输运性质；DNA碱基与石墨烯纳米带的共价偶联：负微分电阻，整流，和热电性能；缺陷半赫斯勒合金Nb0.8CoSb中的亚晶格短程有序和修正的电子结构。本项目成果可为实验制备分子电学、热学及热电器件提供理论指导。