Wrzesińska Angelika, Wypych-Puszkarz Aleksandra, Bobowska Izabela, Ulański Jacek
Department of Molecular Physics, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland.
Polymers (Basel). 2021 Mar 20;13(6):956. doi: 10.3390/polym13060956.
There is an urgent need for the development of elastic dielectric materials for flexible organic field effect transistors (OFETs). In this work, detailed analysis of the AC and DC electrical conductivity of a series of flexible poly(dimethylsiloxane) (PDMS) polymers crosslinked by metal-ligand coordination in comparison to neat PDMS was performed for the first time by means of broadband dielectric spectroscopy. The ligand was 2,2-bipyridine-4,4-dicarboxylic amide, and Ni, Mn, and Zn were introduced for Cl, Br, and I salts. Introduction of metal salt and creation of coordination bonds resulted in higher permittivity values increasing in an order: neat PDMS < Ni < Mn < Zn; accompanied by conductivity values of the materials increasing in an order: neat PDMS < Cl < I < Br. Conductivity relaxation time plot as a function of temperature, showed Vogel-Fulcher-Tammann dependance for the Br salts and Arrhenius type for the Cl and I salts. Performed study revealed that double-edged challenge can be obtained, i.e., dielectric materials with elevated value of dielectric permittivity without deterioration too much the non-conductive nature of the polymer. This opens up new perspectives for the production of flexible dielectrics suitable for gate insulators in OFETs. Among the synthesized organometallic materials, those with chlorides salts are the most promising for such applications.
迫切需要开发用于柔性有机场效应晶体管（OFET）的弹性介电材料。在这项工作中，首次通过宽带介电谱对一系列通过金属-配体配位交联的柔性聚二甲基硅氧烷（PDMS）聚合物与纯PDMS的交流和直流电导率进行了详细分析。配体为2,2-联吡啶-4,4-二羧酸酰胺，引入Ni、Mn和Zn分别对应Cl、Br和I盐。金属盐的引入和配位键的形成导致介电常数升高，顺序为：纯PDMS < Ni < Mn < Zn；同时材料的电导率顺序为：纯PDMS < Cl < I < Br。电导率弛豫时间随温度的变化曲线表明，Br盐符合Vogel-Fulcher-Tammann关系，而Cl盐和I盐符合Arrhenius类型。所进行的研究表明，可以实现双重挑战，即获得具有较高介电常数的介电材料，同时又不会过度损害聚合物的非导电性质。这为生产适用于OFET栅极绝缘体的柔性电介质开辟了新的前景。在合成的有机金属材料中，含氯盐的材料最有希望用于此类应用。
