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

• Main Authors: Cheng-Wei Liu, 劉鎮瑋
• Other Authors: Jyh-Shyang Wang
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/kq89pj

碩士 === 中原大學 === 物理研究所 === 104 === 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.