Molecular Weight-Induced Structural Transition of Liquid-Crystalline Polymer Semiconductor for High-Stability Organic Transistor
Molecular Weight-Induced Structural Transition of Liquid-Crystalline Polymer Semiconductor for High-Stability Organic Transistor
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DOI：
10.1002/adfm.201101021
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发表时间：
2011-12-06
影响因子：
19
通讯作者：
Lee, Sangyoon
中科院分区：
文献类型：
--
作者：
Kim, Do Hwan;Lee, Jiyoul;Lee, Sangyoon
为了制备在偏置应力下具有高电稳定性的聚合物场效应晶体管（PFFET），最小化由无序区引起的电荷俘获点密度是至关重要的。在这里，我们报告的PFREX具有优异的电稳定性相媲美的单晶有机半导体，通过具体控制的分子量（MW）的供体-受体型共聚物半导体，聚（双十二烷基季噻吩-alt-双十二烷基联噻唑）。我们发现，微波诱导的热结构从液晶相到半结晶相的转变强烈影响器件性能（电荷载流子迁移率和电偏压稳定性）以及纳米结构，如分子有序性和形态特征。特别地，对于具有22 kDa的MW的聚合物，在环境条件下在延长的偏置应力期间（约50 000 s），传递曲线变化很小（Δ V-th = 3，类似于4 V）。这种电偏压稳定性的增强可以归因于通过分子量的优化在电介质表面上高度有序的共聚物半导体液晶纳米结构。
In order to fabricate polymer field-effect transistors (PFETs) with high electrical stability under bias-stress, it is crucial to minimize the density of charge trapping sites caused by the disordered regions. Here we report PFETs with excellent electrical stability comparable to that of single-crystalline organic semiconductors by specifically controlling the molecular weight (MW) of the donor-acceptor type copolymer semiconductors, poly (didodecylquaterthiophene-alt-didodecylbithiazole). We found that MW-induced thermally structural transition from liquid-crystalline to semi-crystalline phases strongly affects the device performance (charge-carrier mobility and electrical bias-stability) as well as the nanostructures such as the molecular ordering and the morphological feature. In particular, for the polymer with a MW of 22 kDa, the transfer curves varied little (Delta V-th = 3 similar to 4 V) during a period of prolonged bias stress (about 50 000 s) under ambient conditions. This enhancement of the electrical bias-stability can be attributed to highly ordered liquid-crystalline nanostructure of copolymer semiconductors on dielectric surface via the optimization of molecular weights.