Naphthodithiophene Diimide (NDTI)-Based Semiconducting Copolymers: From Ambipolar to Unipolar n-Type Polymers
Naphthodithiophene Diimide (NDTI)-Based Semiconducting Copolymers: From Ambipolar to Unipolar n-Type Polymers
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DOI：
10.1021/ma502306f
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发表时间：
2015-02-10
期刊：
影响因子：
5.5
通讯作者：
Takimiya, Kazuo
中科院分区：
文献类型：
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作者：
Nakano, Masahiro;Osaka, Itaru;Takimiya, Kazuo
一系列基于萘并二噻吩二酰亚胺（NDTI）的半导体聚合物具有各种共聚单体单元，即，分别以2，7-二溴-NDTI和2，7-双（三甲基锡烷基）-NDTI为原料，通过Stille偶联或碘化铜辅助的Stille偶联反应合成了噻吩并亚乙烯基（TV）、萘并[1，2-B：5，6-b ']二噻吩（NDT）、亚乙烯基（V）、苯并[c][1，2，5]噻二唑（BTz）和萘并[1，2-c：5，6-c']双[1，2，5]噻二唑（NTz）。用循环伏安法和光电子能谱法估算了它们的HOMO和LUMO能级。基于NDTI的聚合物的HOMO能级受到共聚单体单元的电子性质的强烈影响。相比之下，它们的LUMO能级几乎相同，这可能是由于它们在NDTI部分上的局部LUMO。所有的聚合物都表现出在场效应晶体管（FET）中的空气稳定电子传输，这要归功于它们的低LUMO（类似于-4.0 eV），作为双极型（PNDTI-TV，-NDT，类似于0.082 cm（-2）V1 s1，mu（e）=类似于0.029 cm（-2）V-1 s（-1））或单极n沟道材料（PNDTI-V，-BTz，PNDTI-NTz，mu（e）=类似于0.21 cm（-2）V-1 s（-1）），取决于它们的HOMO能级。这些结果表明，NDTI基聚合物中的活性载体的类型可以通过共聚单体单元的性质来控制。此外，二维掠入射X射线衍射（2D GIXD）表明，具有线性主链结构和支化烷基链之间的大空间的聚合物倾向于提供具有边缘取向的组织良好的结晶薄膜，与其FET器件中的良好输运特性一致。
A series of naphthodithiophene diimid (NDTI) based semiconducting polymers with various comonomer units, i.e., thienylenevinylene (TV), naphtho[1,2-b:5,6-b']dithiophene (NDT), vinylene (V), benzo[c][1,2,5]thiadiazole (BTz), and naphtho[1,2-c:5,6-c']bis[1,2,5]thiadiazole (NTz), were synthesized by Stille coupling or copper iodide-assisted Stille coupling using 2,7-dibromo-NDTI or 2,7-bis(trimethylstannyl)-NDTI, respectively. Their HOMO and LUMO energy levels were estimated by cyclic volttammetry and photoelectron spectroscopy. The HOMO energy levels of the NDTI-based polymers were strongly affected by the electronic nature of the comonomer units. In contrast, their LUMO energy levels were almost identical, likely owing to their localized LUMOs on the NDTI moiety. All the polymers showed air-stable electron transport in the field-effect transistors (FETs), thanks to their low-lying LUMO (similar to-4.0 eV), as ambipolar (PNDTI-TV, -NDT, similar to 0.082 cm(-2) V1 s1, mu(e) = similar to 0.029 cm(-2) V-1 s(-1)) or unipolar n-channel materials (PNDTI-V, -BTz, PNDTI-NTz, mu(e) = similar to 0.21 cm(-2) V-1 s(-1)), depending on their HOMO energy levels. These results indicate that the type of active carrier in the NDTI-based polymers can be controlled by the nature of comonomer units. Moreover, the two-dimensional grazing incidence X-ray diffraction (2D GIXD) indicated that the polymers with linear backbone structures and large space between the branched alkyl chains tend to afford well-organized crystalline thin film with the edge-on orientation, consistent with good transport characteristics in their FET devices.