Polymer-Free Electronic-Grade Aligned Semiconducting Carbon Nanotube Array
Polymer-Free Electronic-Grade Aligned Semiconducting Carbon Nanotube Array
复制标题
无聚合物电子级取向半导体碳纳米管阵列
DOI：
10.1021/acsami.7b06850
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发表时间：
2017-08-30
影响因子：
9.5
通讯作者：
Gopalan, Padma
中科院分区：
文献类型：
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作者：
Joo, Yongho;Brady, Gerald J.;Gopalan, Padma
共轭聚合物通常用于在有机溶剂中选择性地将半导体碳纳米管（S-CNT）与其金属对应物分离。聚合物包裹的S-CNT可以容易地从有机溶剂加工成CNT阵列，用于可扩展的器件制造。虽然共轭聚合物对于分选和器件制造是必不可少的，但是非常希望完全去除它们，因为它们限制了器件的电子特性。在这里，我们使用市售的聚合物，即聚[（9，9-二辛基芴基1 - 2，7-二基）-aft-co-（6，6 '-（2，2'-联吡啶））]（PFO-BPy），通过浮动蒸发自组装（FESA）工艺对大直径S-CNTs进行选择性分选并制备基于CNT阵列的场效应晶体管（FET）。我们报告了使用金属螯合辅助聚合物去除（McAPR）工艺从FESA对齐的S-CNT阵列中定量去除聚合物包装材料。在FESA上实现这一过程。薄膜的制备需要将聚合物选择性热降解成低聚物，并结合优化溶剂类型和金属络合反应的温度。所得的S-CNT阵列FET器件表明，原始CNT的电子特性通过该过程得以保留。光学显微镜，紫外-可见光谱，和X射线光电子能谱（XPS）被用来表征定量聚合物的去除。我们定量地描述FET器件，通过比较聚合物去除前后来分析FET的基本特性（迁移率（μ）、导通电导（G（on））和接触电阻（2 R（c）。在对齐的CNT阵列中完全去除聚合物包装物而不对器件性能产生不利影响的能力开辟了FET以外的应用，进入光致发光和生物传感。
Conjugated polymers are used commonly to selectively sort semiconducting carbon nanotubes (S-CNTs) from their metallic counterparts in organic solvents. The polymer-wrapped S-CNTs can be easily processed from organic solvents into arrays of CNTs for scalable device fabrication. Though the conjugated polymers are essential for sorting and device fabrication, it is highly desirable to remove them completely as they limit the electronic properties of the device. Here, we use a commercially available polymer, namely, poly[(9,9-dioctylfluoreny1-2,7-diy1)-aft-co-(6,6'-(2,2'-bipyridine))] (PFO-BPy), to sort large-diameter S-CNTs with ultrahigh selectivity and fabricate CNT-array-based field effect transistors (FETs) via a floating evaporative self assembly (FESA) process. We report quantitative removal of the polymer wrapper from the FESA aligned S-CNT arrays using a metal-chelation-assisted polymer removal (McAPR) process. The implementation of this process on FESA. films requires the selective thermal degradation of the polymer into oligomers, combined with optimization of the solvent type and temperature of the metal complexation reaction. Resulting S-CNT array FET devices show that the electronic properties of pristine CNT are preserved through this process. Optical microscopy, UV-vis spectroscopy, and X-ray photoelectron spectroscopy (XPS) were used to characterize the quantitative polymer removal. We quantitatively describe the FET devices to analyze the fundamental characteristics of FETs (mobility (mu), on-conductance (G(on)), and contact resistance (2R(c))) by comparing before and after polymer removal. The ability to completely remove the polymer wrapper in aligned CNT arrays without adversely affecting the device properties opens up applications beyond FETs into photovoltaics and biosensing.