Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA.
Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
Adv Mater. 2017 Jul;29(27). doi: 10.1002/adma.201700411. Epub 2017 May 10.
Molecular doping of organic electronics has shown promise to sensitively modulate important device metrics. One critical challenge is the disruption of structure order upon doping of highly crystalline organic semiconductors, which significantly reduces the charge carrier mobility. This paper demonstrates a new method to achieve large modulation of charge carrier mobility via channel doping without disrupting the molecular ordering. Central to the method is the introduction of nanopores into the organic semiconductor thin films via a simple and robust templated meniscus-guided coating method. Using this method, the charge carrier mobility of C -benzothieno[3,2-b]benzothiophene transistors is boosted by almost sevenfold. This paper further demonstrates enhanced electron transport by close to an order of magnitude in a diketopyrrolopyrrole-based donor-acceptor polymer. Combining spectroscopic measurements, density functional theory calculations, and electrical characterizations, the doping mechanism is identified as partial-charge-transfer induced trap filling. The nanopores serve to enhance the dopant/organic semiconductor charge transfer reaction by exposing the π-electrons to the pore wall.
有机电子的分子掺杂已显示出可灵敏调节重要器件参数的潜力。一个关键的挑战是，在高度结晶的有机半导体掺杂时，结构有序性会被破坏，这会显著降低载流子迁移率。本文展示了一种新的方法，通过通道掺杂来实现载流子迁移率的大幅调节，而不会破坏分子的有序性。该方法的核心是通过简单而稳健的模板引导的弯月面涂覆方法，在有机半导体薄膜中引入纳米孔。使用这种方法，C-苯并[3,2-b]苯并噻吩晶体管的载流子迁移率提高了近七倍。本文还进一步证明，在基于二酮吡咯并吡咯的供体-受体聚合物中，电子输运能力提高了近一个数量级。通过光谱测量、密度泛函理论计算和电学特性分析，确定掺杂机制为部分电荷转移诱导的陷阱填充。纳米孔通过将π电子暴露于孔壁来增强掺杂剂/有机半导体的电荷转移反应。
