三维导电纳米结构超分辨激光直写技术研究

Conductive nanostructures, working as nano-carriers in charge transportation, have played an indispensable role in the fields of energy technology, information technology and nanobiology technology. For the extraordinary properties in controlled conductivity, nanometer-size effect and highly spatial utilization rate, 3D conductive nanostructures produce advantages in rendering high-performance opto-electronic micro/nanodevices with lightweight and spatially integration ability. However, limited fabrication method prevents the development of opto-electronic nanodevices. The ever increasing pursuit of superdevice with overwhelming performances imposes enormous demands on developing an advancing fabrication technique to realize 3D structures with diverse geometries, extremely small size and high conductivity. To address this problem, in this project, we aims to demonstrate highly conductive 3D nanostructures with optical two-beam super-resolution direct laser writing technique. As is well-know, direct laser writing employing two-photon absorption is capable of producing spatially resolved microstructures. Owing to the fundamental limit set up by the light diffraction, resolution in the fabrication is restrained in the sub-wavelength scale. Based on former studies on super-resolution fabrication methods, we have realized 9 nm polymer nanowire. In comparison, to realize conductive 3D nanostructure requires new super-resolution mechanism as well as suited materials and adapted fabrication techniques. The two-beam super-resolution fabrication technique employs one initiation beam for initiating photoreaction and producing structures, and the other inhibition beam for inhibiting photoreaction and preventing structure formation, which results in a photoinhibition-inhibited process for reducing the size of structures as fabricated. In this case, we will design and synthesize metal(carbon)/polymer hybrid photoresin composites with formulation suitable for implementing the photoinitiation-inhibited mechanism. A dynamic model will be built to study the interaction between the light and each components including conductive parts and dielectric parts in the photoresin. We will investigate the influence of tuning multi-parameters, such as the wavelength, polarization, phase, pulse width and pulse repetition rate, in the light field imposed by the focused two laser beams on the material reactions. How to confine series of interacted reactions containing photopolymerization, photoreduction and photothermalization in the nanoscale by using two-beam method will be studied. We will optimize the fabrication condition, such as the scanning speed, the scanning route and the exposure power, to fabricate a robust 3D nanostructures with the hybrid photoresin composites. The fabrication process and the post treatment methods will be explored to augment the conductivity of nanostructures. Combined with the material development and two-beam super-resolution fabrication technique, we commit resolving a long lasting problem on a mutual suppression between the size, the geometry and the conductivity in direct laser writing of conduction 3D structures. Eventually, we can realize 3D conductive nanostructures with its conductivity comparable to common conductors and explore their applications in functional devices.

导电纳米结构作为纳米尺度电荷传输载体在能源技术、电子信息技术、纳米生物技术领域发挥有不可替代作用。利用可控电导性能、纳米尺寸效应和高空间利用率，三维导电纳米结构在功能器件应用中具有性能优异、重量轻和可集成化等优势。然而受目前加工技术限制，迫切需要一种能制备具有高导电性能、结构构型多样化和纳米尺寸三维结构的方法，针对这一问题，在前期完成激光直写特征尺寸可达9nm的聚合物结构加工技术基础上，本项目拟发展双光束超分辨激光直写三维导电纳米结构方法，结合金属(碳)/聚合物纳米复合光学树脂设计和合成控制，发展光场多参量联合调控复合材料光聚合、光还原等多重光反应纳米尺度控制方法，优化加工流程设计、加工后处理方式等加工工艺，解决激光直写加工功能微纳结构方法中结构性能、尺寸和几何构型相互制约问题，实现电导率与常规导电材料相当的三维导电纳米结构激光直写加工，并探索其尺寸、构型和导电特性的功能应用。

随着下一代纳米光电功能器件技术的发展，新的功能应用不仅需要在微纳尺度进一步控制纳米结构导电性能和尺寸特征，还对其几何构型多样化、特征尺寸、光学特性、力学特性提出了新的要求。作为纳米尺度电荷传输载体，导电微纳结构在能源技术、电子信息技术、纳米生物技术领域可发挥重要作用，其中，三维导电纳米结构，因其特殊的电导性能和纳米尺寸效应，在功能器件应用中具有性能优异、重量轻和可集成化等优势。然而受目前加工技术限制，迫切需要一种能制备具有高导电性能、结构构型多样化和纳米尺寸三维结构的加工材料和加工方法。针对这一问题，本项目发展了双光束超分辨激光直写三维导电纳米结构方法，结合金属(碳)/聚合物纳米复合光学树脂设计和合成控制，发展光场多参量联合调控复合材料光聚合、光还原等多重光反应纳米尺度控制方法，优化加工流程设计、加工后处理方式等加工工艺，研究并解决激光直写加工功能微纳结构方法中结构性能、尺寸和几何构型相互制约问题。在项目研究过程中，我们开发了聚合物/有机半导体，聚合物/金属，水凝胶/金属三种不同材料体系。利用光学超分辨技术，完成单像素加工分辨率为45nm，像素间距96nm，导电线的加工分辨率达到65nm。基于新型光敏树脂材料体系，通过发展加工工艺和方法，完成包括木堆积结构、立方体结构、螺旋线圈等三种以上几何构型结构制备。微纳金属导线电导性达到2*107 S/cm。