Department of Chemistry , University of California , Berkeley , California 94720 , United States.
Division of Molecular Biophysics and Integrated Bioimaging , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States.
J Am Chem Soc. 2018 Aug 1;140(30):9574-9580. doi: 10.1021/jacs.8b04679. Epub 2018 Jul 18.
The functional integration of atomically defined graphene nanoribbons (GNRs) into single-ribbon electronic device architectures has been limited by access to nondestructive high-resolution imaging techniques that are both compatible with common supports such as Si or Si/SiO wafers and capable of resolving individual ribbons in dilute samples. Conventional techniques such as scanning probe (AFM, STM) or electron microscopy (SEM, TEM) have been restricted by requisite sample preparation techniques that are incompatible with lithographic device fabrication. Here we report the design and synthesis of ultralong (∼10 μm) cove-type GNRs (cGNRs) featuring azide groups along the edges that can serve as a universal handle for late-stage functionalization with terminal alkynes. Copper-catalyzed click-chemistry with Cy5 fluorescent dyes gives rise to cGNRs decorated along the edges with fluorescent tags detectable by optical microscopy. The structures of individual dye-functionalized cGNRs spin-coated from a dilute solution onto transparent and opaque insulating substrates were resolved using diffraction-limited fluorescence microscopy and super-resolution microscopy (SRM) imaging techniques. Analysis of SRM images reveals an apparent width of cGNRs in the range 40-50 nm and lengths in excess of 10 μm, the longest GNRs imaged to date. Isolated cGNRs can even be distinguished from bundles and larger aggregates as long as the center-to-center distance is greater than the apparent width.
原子定义的石墨烯纳米带（GNRs）的功能集成到单条电子器件结构中受到限制，因为缺乏既与 Si 或 Si/SiO 晶片等常见衬底兼容又能解析稀样中单条纳米带的无损高分辨率成像技术。传统的技术，如扫描探针（AFM、STM）或电子显微镜（SEM、TEM），受到与光刻器件制造不兼容的必需样品制备技术的限制。在这里，我们报告了设计和合成超长（~10μm） Cove 型 GNRs（cGNRs）的方法，其边缘具有叠氮基团，可作为后期功能化末端炔烃的通用手柄。具有 Cy5 荧光染料的铜催化点击化学导致 cGNRs 沿边缘装饰有荧光标记，可通过光学显微镜检测到。使用具有衍射极限的荧光显微镜和超分辨率显微镜（SRM）成像技术，解析了从稀溶液旋涂到透明和不透明绝缘衬底上的单个染料功能化 cGNRs 的结构。对 SRM 图像的分析表明，cGNRs 的表观宽度在 40-50nm 范围内，长度超过 10μm，这是迄今为止成像的最长 GNRs。只要中心到中心的距离大于表观宽度，就可以将孤立的 cGNRs 与束和更大的聚集体区分开来。
