Embedded Dipole Self‐Assembled Monolayers for Contact Resistance Tuning in p‐Type and n‐Type Organic Thin Film Transistors and Flexible Electronic Circuits
Embedded Dipole Self‐Assembled Monolayers for Contact Resistance Tuning in p‐Type and n‐Type Organic Thin Film Transistors and Flexible Electronic Circuits
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DOI：
10.1002/adfm.201804462
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发表时间：
2018-09
影响因子：
19
通讯作者：
Andreas Petritz;Markus Krammer;E. Sauter;Michael Gärtner;Giulia Nascimbeni;B. Schrode;A. Fian;H. Gold;Andreea-Gabriela Cojocaru;Esther Karner‐Petritz;R. Resel;A. Terfort;E. Zojer;M. Zharnikov;K. Zojer;B. Stadlober
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作者：
Andreas Petritz;Markus Krammer;E. Sauter;Michael Gärtner;Giulia Nascimbeni;B. Schrode;A. Fian;H. Gold;Andreea-Gabriela Cojocaru;Esther Karner‐Petritz;R. Resel;A. Terfort;E. Zojer;M. Zharnikov;K. Zojer;B. Stadlober
基于嵌入偶极自组装单分子膜(SAM)的强大概念，设计了高导电性的界面层，使有机薄膜晶体管的接触电阻可以在三个数量级上调节，最小值远低于1kΩcm。这不仅允许在刚性和柔性衬底上实现极具竞争力的p型(基于并五苯)器件，还使得使用相同的电极材料(Au)实现具有类似特性的n型(基于C60)晶体管成为可能。作为在更复杂的器件结构中实现高电势的典型例子，制作了静态增益为220V/V的柔性有机反相器和工作在4V以下的5级环形振荡器，其级频在理论上可达到的最大值范围内。采用各种互补的实验和模拟技术，结果表明：通过适当的偶极子取向消除注入势垒，以及通过有意地减小SAM厚度来增强载流子的传输，可以降低接触电阻。值得注意的是，将偶极基团嵌入形成SAM的分子的骨架中允许在不改变活性层生长的情况下利用它们的有益效果。
Based on the powerful concept of embedded dipole self‐assembled monolayers (SAMs), highly conductive interfacial layers are designed, which allow tuning the contact resistance of organic thin‐film transistors over three orders of magnitude with minimum values well below 1 kΩ cm. This not only permits the realization of highly competitive p‐type (pentacene‐based) devices on rigid as well as flexible substrates, but also enables the realization of n‐type (C60‐based) transistors with comparable characteristics utilizing the same electrode material (Au). As prototypical examples for the high potential of the presented SAMs in more complex device structures, flexible organic inverters with static gains of 220 V/V and a 5‐stage ring‐oscillator operated below 4 V with a stage frequency in the range of the theoretically achievable maximum are fabricated. Employing a variety of complementary experimental and modeling techniques, it is shown that contact resistances are reduced by i) eliminating the injection barrier through a suitable dipole orientation, and by ii) boosting the transmission of charge carriers through a deliberate reduction of the SAM thickness. Notably, the embedding of the dipolar group into the backbones of the SAM‐forming molecules allows exploiting their beneficial effects without modifying the growth of the active layer.