Emission Behaviors of Quantum Dots Linked onto Synthesized Metal Nanoparticles

• Main Authors: Cheng-Jin Cai, 蔡誠晉
• Other Authors: 楊志忠
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/sfb7r8

碩士 === 國立臺灣大學 === 光電工程學研究所 === 107 === Eight different metal nanoparticle (NP) samples in total of different localized surface plasmon (LSP) resonance wavelengths, including two pure Au NP samples, two pure Ag NP samples of quite different sizes, and four Ag/Au core/shell NP samples of different compositions are synthesized. After linking with PEGs of different molecular weights, those NP samples are linked with quantum dots (QDs) for observing the emission behaviors of the QDs. Scanning electron microscopy images show the linkage of QDs onto metal NPs of different samples. Time-resolved photoluminescence (PL) and internal quantum efficiency (IQE) measurements are undertaken for understanding the QD emission efficiencies. The consistent PL decay time and IQE show that the pure Ag NP samples with residual surface citrate have shorter PL decay times and higher IQEs, when compared with the NP samples of pure Au. Also, between the two pure Au NP samples, the one with residual surface citrate has a shorter PL decay time and a higher IQE, when compared with the other pure Au NP sample with residual surface CTAC. These results are generally attributed to the higher efficiency of replacing citrate by PEG, when compared to CTAC. Among those Ag/Au core/shell NP samples, generally a higher Au content leads to a longer PL decay time and a lower IQE. Based on these results, we can optimize the metal NP condition for maximizing the color conversion efficiency from a blue-light source into red light through the LSP-resonance enhanced QD absorption-reemission process.