貴金屬奈米晶體，如銀奈米立方體(AgNCs)，具有優異的電漿子特性，使其可被用作高靈敏度光電傳感器，如表面增強拉曼散射(SERS)。以AgNCs 形成之二聚體奈米結可通過AgNCs間強“電漿子耦合”的效應，可以進一步提高AgNC的傳感性能。由於“電漿子耦合”的強度對奈米結中電漿子奈米晶體之間的次奈米級(sub-nanoscale)間距有高度的敏感性，因此二聚體奈米結可利用因為外部刺激源下產生之AgNC 間距變化來檢測外部刺激源。例如，被導電材料包圍的二聚體奈米結在外部光照射下因為二聚體奈米結周遭之電磁場產生導電材料的重排，這導致 AgNC 之間的間距發生變化，從而改變拉曼散射訊號的靈敏度。拉曼散射訊號靈敏度變化可用於檢測外加光源之強度。在這裡，利用相同的原理，將磁性材料包圍於二聚體奈米結周遭作為感測平台來檢測外部磁場 (MF) 的方向和強度。結果表明，奈米結中 AgNCs 間距的變化也是來自於磁性材料在外部磁場下的重排所引起的，且此重排很大程度上取決於磁性材料與 AgNC 表面配體之間的相互作用以及由AgNC 表面上的配體構造所產生的空間排斥力。與沒有外部磁場下二聚體奈米結的拉曼散射光譜相比，在外部磁場影響下二聚體奈米結的拉曼散射訊號的增強因子可高達 ~900%，這使得具有磁性材料的二聚體奈米結適用於“磁場”感測上之應用。
電漿子奈米二聚體除了可以利用二聚體奈米晶體之間距對拉曼散射訊號之高靈敏度，故被廣泛用於感測各式外加刺激源外，奈米晶體因為於外加光源刺激下能於奈米晶體周遭產生熱電子，這些熱電子可以與電漿子奈米結周圍的發光材料相互作用，導致發光材料的發光行為發生變化，理論上此二聚體奈米結能有效地加強光電轉換效率，故亦被廣泛用於光電轉換相關之應用。為了研究二聚體於外加光源下所產生熱電子對光電轉移效率之影響，在此將發光材料(導電高分子)引入二聚體奈米結中以生成奈米複合材料，以研究發光材料在電漿子誘導的電磁場下之發光增強因子的變化。於外加光照下奈米複合材料的發光增強因子強烈依賴於 (1) 電子於材料間的轉移方向和驅動力：由發光材料的相對軌道能量和二聚體奈米結的 LSPR 模式來控制； (2) 二聚體奈米結周圍產生的熱電子的位置和數量：受二聚體奈米結的構相和照射光強度/波長的控制。這些結果表明可應用於設計光激發之光電設備、固態照明、生物傳感等需要高發光效率之複合材料。

Noble metal nanocrystals, such as silver nanocubes, AgNCs, have excellent plasmonic properties, allowing them to be used as high sensitivity optoelectronic sensors, such as Surface-enhanced Raman scattering, SERS. And the sensing performance of AgNC can be further improved by forming dimer nanojunction with strong “plasmonic coupling”. Since the strength of “plasmonic coupling” is highly sensitive to the sub-nanoscale spacing between plasmonic nanocrystals in nanojunctions, dimer nanojunction can be used to detect external stimuli that can change the spacing of AgNCs in the nanojunction. For example, dimer nanojunctions surrounded by conductive materials exhibit rearrangement of conductive materials under external irradiation, which leads to a change in the spacing between the AgNCs and thus changes the sensitivity of Raman scattering signals. This change in sensitivity of the Raman scattering signal can be used to detect the strength of irradiation. Here, we utilize the same principle to detect the direction and strength of an external magnetic field (MF) using dimer nanojunctions surrounded with magnetic materials as a sensing platform. The results exhibit that the changes of AgNCs spacing in the nanojunction is also caused by the rearrangement of the magnetic material under an external MF, which strongly depends on the interaction between the magnetic material and the ligands on AgNC surface and the steric repulsion generated by the ligand configuration on AgNC surface. Compared with the Raman spectrum without an external MF, the enhancement factors (EF) of the Raman scattering signals under an external MF can reach up to ~900 %, which makes dimer nanojunctions with magnetic materials suitable for “magnetic field” sensing applications.
In addition to utilizing the high sensitivity of the distance between dimer nanocrystals to Rama scattering signals, plasmonic dimer nanojunctions were widely used in sensing various external stimuli. Hot electrons can be generated around nanocrystals under irradiation, and these hot electrons can interact with the luminescent material around the plasmonic nanojunction, resulting in a change in the luminescent behavior of the luminescent material. Theoretically, this dimer nanojunction can effectively enhance photoelectric conversion efficiency. To study the effect of hot electrons generated by the dimer nanojunction under an external light source on the photoelectric transfer efficiency, the large-scale uniform plasmonic dimer nanojunction composite with luminescent materials can be fabricated by changing magnetic materials as before. Similar to the magnetic materials nanojunction composite, it is obtained by substituting luminescent materials with magnetic materials. Here we introduced different conducting polymer (emissive materials) into dimer nanojunctions to generate composites to study the changes in the emission EF of emissive materials under plasmon-induced electromagnetic fields. The emission EF of nanocomposites under irradiation strongly depended on (1) the direction and driving force of electron transfer: controlled by the relative orbital energies of emissive material and LSPR modes of the dimer nanojunction; (2) the position and number of hot electrons generated around the dimer nanojunction: controlled by the conformation of dimer nanojunction and the intensity/wavelength of irradiation. These results paved the way for designing highly emissive composites for optically stimulated optoelectronic devices, solid-state lighting, biosensing et.al.

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