利用電漿奈米天線使無鎘膠體量子點超快速自激發光

Ultrafast spontaneous light emission in Cadmium-free quantum dots using plasmonic nanoantennas

劉鎮瑋(Cheng-Wei Liu)

指導教授 ： 王智祥 ； 院繼祖

中原大學/理學院/物理研究所/碩士(2016年)

https://doi.org/10.6840/cycu201600469

摘要

溶液加工納米材料（NMs）備受關注，由於他們的獨特的光物理和材料特性已被應用在生醫光學和光電元件。近年來，量子點（QD）顯示器已經由索尼和三星商品化，它可以超越傳統的LED的顯示器。不幸的是，最成熟的納米材料都使用含重金屬的半導體化合物，例如CdSe，CdTe和PbSe。在此，利用低毒性或甚至環保的納米材料代替。近年來，無重金屬的奈米材料，如I-III-VI CuInS2量子點，金納米簇和碳點（CDs）已經研發出來，這將取代有毒的鎘/含鉛量子點。不幸的是，這些“綠色”NMs光的物理特性表現平平，例如:在固態時，低光激螢光量子產率的和較長的輻射生命期。透過Purcell Effect解決這些問題，將具有寬頻譜電漿共振的納米天線用於偶合發光體。在此，三種類型的“綠色”奈米材料:CNDs、core/shell CuInS2 / ZnS量子點以及金屬納米簇。利用時間和空間解析的PL光譜進行量測分析。樣本配置包括金薄膜塗覆於基板，摻雜了“綠色”NMs的薄介電層以及電漿納米天線。發現就算三種有不同PL發光機制的NMs耦合到混合模態的納米天線，這些發光層的PL可大幅增強並伴隨著大量PL 生命期縮短。輻射衰減速率的加速度是藉由實驗數據觀察到的行為。利用簡單的方法設計出“綠色”且sub-nanosecond PL生命期的光源，這對它們發展於發光元件是相當有幫助。

關鍵字

膠體量子點 ； 奈米天線 ； 奈米材料 ； 金奈米粒子 ； 螢光增強

並列摘要

Solution-processed nanomaterials (NMs) have attracted much attention owing to their unique photo-physical and materials properties that have been applied in a variety of promising applications in biophotonics and optoelectronics. Recently, quantum-dot (QD) based displays have been commercialized by Sony and Samsung, which can outperform conventional LED-based displays. Unfortunately, the most mature nanomaterial systems all rely on heavy-metal-containing semiconductor compounds, such as CdSe, CdTe, and PbSe, which would be replaced with less toxic or even eco-friendly nanomaterials. Recently, heavy-metal-free NMs, such as I-III-VI CuInS2 QDs, gold nanoclusters and carbon dots (CDs) have been developed, which would be alternatives to toxic Cd/Pb based QDs. Unfortunately, those “green” NMs only hold moderate photo-physical properties, such as low photoluminescence (PL) quantum yields in the solid states and long radiative lifetime. To address these issues, the plasmonic nanoantennas with broad resonance bandwidth can be used to couple spectral broad light emitters thanks to the Purcell effect. Here, three types of "green" NMs, namely CDs, core/shell CuInS2/ZnS QDs, and metal nanoclusters, were investigated using steady-state, time-resolved and spatial resolved PL spectroscopy. The whole sample configuration consist of gold thin film coated substrate, a thin dielectric layer doped with "green" NMs, and plasmonic nanoantennas. We found that upon coupling to such hybrid nanoantennas, In despite of distinct PL emission mechanism of three-type NMs, the PL emission of those emitters can be enhanced accompanied with large PL lifetime shortening. Based on the analyses of the experimental data, large acceleration of radiative decay rates is responsible for the observed behavior. Our demonstrate can pave a way to further design "green" light sources with sub-nanosecond PL lifetime, which is much beneficial for their applications in light-emitting related devices.

並列關鍵字

colloidal quantum dots ； nanoantennas ； nanomaterials ； Purcell effect ； Gold nanoparticles ； fluorescence enhancement

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