【作者】 李瑞；

【导师】 彭伟；

【作者基本信息】 大连理工大学 ， 电子信息（专业学位）， 2023， 硕士

【摘要】 表面等离激元是存在于金属与介质分界面上的电子集体振荡,具有亚波长、空间局域、近场增强等奇异的光学性能,在纳米尺度的光操控、单分子水平的生物探测以及突破衍射极限的高分辨率光学成像等领域具有广泛的应用前景。在纳米尺度的光操控方面,基于纳米结构的周期、尺寸、材料等自身物理属性变化的静态等离激元器件受限于设备的单一化性能和昂贵的制作成本,已不能满足许多领域的应用需求。目前,人们已经开发出多种技术手段可实现纳米结构性能的动态调控,如金属氢化物、液晶、可逆电沉积以及导电聚合物等。其中,基于导电聚合物调制的等离激元纳米结构器件因其具有响应速度快、调控范围大、功耗低和循环稳定性好等突出优势,在动态等离激元器件设计和开发方面展现出广阔的实际应用前景。本论文将金属纳米结构作为设计平台,详细讨论了金纳米盘阵列和金纳米盘-孔阵列光谱的局域光场共振特性,通过在其表面集成导电聚合物实现了这两种金属纳米结构光谱的实时可逆调控,为设计和开发高性能有源光电器件提供了有价值的技术参考。论文的主要研究工作如下:为了研究不同导电聚合物对结构的光谱调控特性,基于表面等离激元共振设计并制备了共振波长位于650 nm处的金纳米盘阵列结构,并在结构表面电化学氧化聚合了聚吡咯(PPy)、聚苯胺(PANI)以及聚3,4-乙烯二氧噻吩(PEDOT)薄膜,继而从复合结构的反射光谱、响应速率以及循环稳定性等方面入手,揭示了不同导电聚合物对金纳米盘阵列的光谱调制优势。实验证明,PPy对金纳米盘阵列的光谱调控主要集中于宽波段范围内的强度调制,其余两者则体现为共振波长的动态调控。此外,PANI和PEDOT都展示了低于50 ms的快速切换时间,而PPy的调控优势体现在其超出50次的循环稳定性,这项工作为设计和实现不同应用需求的动态表面等离激元器件提供了指导方案。基于等离激元共振耦合理论设计并分析了金纳米盘-孔阵列的光谱特性,并将PPy和PANI与金纳米盘-孔阵列集成,实现了复合结构等离激元模式的动态开关。结合电子能带理论和复折射率原理分析了导电聚合物在不同外加电压下的吸收和极化特性,由于PPy和PANI在禁带宽度和吸收强度上的差异,,二者在可见光波段范围内对金纳米盘-孔阵列的光谱响应范围不同。同时,实验证明相比于PANI,PPy具有长期耐久性和快速响应的优势,其在超出200次的双电位切换后仍能保持良好的开关性能,为动态表面等离激元强度调制器件的研发提供了行之有效的技术方案。最后,总结了全文并对未来的研究方向进行了展望。更多还原

【Abstract】 Surface plasmon is a kind of collective charge oscillation existing on the sub-interface of conductor and medium,which has extraordinary optical properties such as breaking the diffraction limit,the enhancement of sub-wavelength,spatial locality,and near-field enhancement,etc.They have a wide range of application prospects in advanced fields such as nanoscale light manipulation,single-molecule-level biological detection,and high-resolution optical imaging that breaks the diffraction limit.In the field of nanoscale optical manipulation,statically plasmonic components can no longer meet the needs of many fields of application limited by the single performance of the equipment and the expensive fabrication cost.Various techniques have been developed to achieve dynamic modulation of nanostructure properties,such as metal hydrides,liquid crystals,reversible electrodeposition,and conductive polymers.Among them,the surface plasmonic nanostructure devices modulated by conductive polymers have broad practical application prospects in the design and development of dynamic plasmonic components for their fast response rates,large scope of regulation,low power consumption,and excellent cycle stability.In this thesis,we apply metal nanostructures as a design platform and have thoroughly discussed the local optical field resonance characteristics of the spectrum of Au nanodisk(Au ND)array and Au nanodisk-hole array structures.The spectra of the two metal nanostructures is reversibly modulated in real-time by integrating conductive polymers on their surfaces,which provides a valuable technical reference for the design and development of high-performance active optoelectronic devices.Following is the main research work of the paper:We have designed and prepared the Au ND array with resonance wavelengths at 650 nm based surface plasmon resonance and have electrochemically oxide polymerized polypyrrole(PPy),polyaniline(PANI),and poly(3,4-ethylenedioxythiophene)(PEDOT)films on the surface of the structures.Afterward,we revealed the advantages of different conductive polymers for the spectral modulation of the Au ND array in terms of reflective spectra,response rates,and cycling stability.It is demonstrated that the spectral modulation of the Au ND array by PPy is mainly focused on the intensity modulation in the broad band range,while the others are reflected in the dynamic modulation of the resonance wavelength.In addition,both PANI and PEDOT exhibit fast switching times below 50 ms,while the advantage of PPy is reflected in its stability beyond 50 cycles,which provides guidance for designing and implementing dynamic surface plasmonic components for different applications.Based on the theory of resonant coupling of surface plasmon,we have designed and analyzed the spectral properties of the Au nanodisk-hole array,and integrated PPy and PANI with Au nanodisk-hole array to realize the dynamic switching of plasmonic mode in composite structures.We have investigated the absorption and polarization properties of conductive polymers at different applied voltages combining the electronic energy band theory and the principle of complex refractive index.As the difference in the forbidden band width and absorption intensity between PPy and PANI,the spectral modulation range of the Au nanodisk-hole array enabled by the two conductive polymers is different in the visible light range.Moreover,it is proved that PPy has the advantages of long-term durability and fast response rate compared with PANI,and it can maintain excellent switching performance after more than 200 times two-potential switching,which suggests an effective technical alternative for the research and development of dynamic surface plasmonic intensity modulation devices.更多还原