| 학회 | 한국재료학회 |
| 학술대회 | 2020년 가을 (11/18 ~ 11/20, 휘닉스 제주 섭지코지) |
| 권호 | 26권 1호 |
| 발표분야 | G. 나노/박막 재료 분과 |
| 제목 | Growth Kinetics of Individual Au Spiky Nanoparticles Using Liquid-Cell Transmission Electron Microscopy |
| 초록 | The metal particles have various optical, electrical, and catalytic properties which are related to size and morphology of particles unlike bulk materials. Especially, the Au spiky nanoparticle (SNP) is essential to obtain narrow and tunable surface plasmon resonance (SPR), and it is required to precise control over the size and morphology. For many years, a lot of efforts have been devoted to understand the growth mechanism in solution. Liquid cell transmission electron microscopy has emerged as a wonderful technique for direct observation of particle growth in liquid phase. Also, it allows us to observe structural changes and chemical processes in liquid phase, providing a combination of temporal and spatial resolutions that is not achievable with other characterization techniques. In this work, using in situ liquid cell transmission electron microscopy, we observe the formation of single and multiple Au SNP growth during electron beam irradiation of gold chloride (HAuCl4) solution. We carry out the growth kinetics and morphology transition by varying the molar concentration of HAuCl4 solution and dose rate of electron beam. The particle evolves via a mixture of reaction and Au formation-limited growth, followed by Au formation-limited growth a transition from faceted to roughened surfaces, confirmed by the analysis with different beam sizes and the UV−vis spectra that feature a unique trend of short- and long-wavelength plasmon band shift. Quantitative analyses combined with a theoretical model determine the transition time (tc) of the two regimes and estimate the surface concentration (ci) of the particle with time. Interestingly, tc can be manipulated by the particle density, which alters the surface roughening rate, and the density is modulated by tuning the aforementioned parameters based on DLVO theory. In the end, understanding of these phenomena is expected to provide new insights a new method for synthesizing a Au SNP whose size, morphology, SPR, and density without adding reducing or capping agents. |
| 저자 | 정완길, 최영균, 김봉중 |
| 소속 | 광주과학기술원 신소재공학부 |
| 키워드 | Au spiky nanoparticle; in situ Liquid cell transmission electron microscopy; nucleation; growth |
