金奈米團簇於二氧化矽固態基質之光物理性質研究

Photophysical properties of gold nanoclusters in the silica matrix

姚宗佐(CHONG CHO IO)

指導教授 ： 院繼祖

中原大學/理學院/奈米科技碩士學位學程/碩士(2022年)

https://doi.org/10.6840/cycu202201679

摘要

金奈米團簇因其良好光學特性、表面化學性質及大的斯托克斯位移，廣泛應用在各個領域當中。原子精確的金奈米團簇可通過改變表面的配體基團修改團簇的發光特性，但對於合成紅色發射光高量子效率的金奈米團簇仍然有相當大的挑戰，因其較小的輻射複合衰變率和非輻射輻合衰變率的增大，從而降低了團簇量子效率及總體的發光效率。本論文中，以溶膠-凝膠法將氨基矽烷接技穀胱甘肽穩定金奈米團簇，製備出電子態耦合的二氧化矽金金奈米團簇複合材料，進而研究光物理，化學和結構的特性。研究發現複合材料表現出獨特的光學特性，隨著光譜從黃色發射紅移到深紅色發射區域，譜線寬度縮窄，量子效率提高到70%，同時吸收波長藍移，斯托克斯位移逐漸增大，複合材料在日光燈下幾乎完全透明。在傅立葉變換紅外光譜和穿透式電子顯微鏡分析下，證明了金奈米團簇與氨基矽烷以共價鍵鍵合，從而限制在多孔二氧化矽的孔洞中，團簇呈現出獨特的排列方式，與傳統金奈米團簇的聚集誘導發射效應截然不同，揭示著電子態耦合的發生。本研究將為通過修改溶膠-凝膠法金屬醇鹽包埋金奈米團簇方式來制定光物理特性及發展成光學元件提供了一個新的方向。

關鍵字

金奈米團簇 ； 紅色發射金奈米團簇 ； 溶膠-凝膠法 ； 氨基矽烷 ； 電子態耦合

並列摘要

Due to their excellent optical properties, surface chemistry, and large stokes shift, gold nanoclusters (AuNCs) were widely utilized in various applications. The optical properties of AuNCs could be tuned up to deep-red/NIR by tailoring their surface ligand, however, red-emissive AuNCs were still difficult to be synthesized, due to small radiative and large non-radiative decay rates, thus reducing their photoluminescence quantum yield (PLQY) and overall efficiency. In this study, electronically-coupled thiolate-AuNCs were fabricated using organo-silane grafting and sol-gel process. It is found that the fabricated AuNCs@silica composite exhibited red-shifted emission from pale-yellow to deep-red emission along with narrowed-line-width and ultrahigh PLQY of 70%. Moreover, the absorption is blue-shifted, leading to broad stokes shift and exhibited high transparency of fabricated composite in ambient light. Transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR) analysis showed that AuNCs were linked to organo-silane through covalent bonding which restricting the AuNCs inside the silica nanopores with distinct arrangement. This mechanism was completely different from traditional aggregation induced emission enhancement (AIEE) where no electronic-coupling were occurred in the former AIEE. Therefore, this work would provide a novel research direction to engineer photophysical properties through modifying sol-gel packing to be utilized in further application in solid-state, such as photovoltaics.

並列關鍵字

Gold nanoclusters ； Red-emissive AuNCs ； Sol-gel process ； Organo-silane ； Electronically-coupled

參考文獻

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