01 February 2012 01 February 2012

Detecting single metal nanoparticle by dark-field microscopy Detecting single metal nanoparticle by dark-field microscopy Jeonghoo kim

Marian High School

Introduction & MotivationIntroduction & Motivation

Dark field microscopy describes microscopy method, in both light and electron

microscopy, which exclude the unscattered beam of the image.

In this experiment, dark field optical microscopy was used to detect single metal

nanoparticles. The goals of this research were to develop the technique to observe nano-

sized particles and to understand the factors that influence the position and line width of the

plasmon band, which is collective motion of the electrons in the particle. The plasmon band

gives rise to the brilliant colors of metal particle samples.

Procedure Procedure

1. Clean the condenser so microscope and give focused picture of

particles.

2. Put the slide with the particles on the microscope stage

3. Drop a oil on the slide , then focus the particle by adjusting the

microscope

4. Take a picture of the particle by using the camera.

5. Use the spectrometer to find the plasmon band of each paritlces.

1. Clean the condenser so microscope and give focused picture of

particles.

2. Put the slide with the particles on the microscope stage

3. Drop a oil on the slide , then focus the particle by adjusting the

microscope

4. Take a picture of the particle by using the camera.

5. Use the spectrometer to find the plasmon band of each paritlces.

Absorbance Mode

Results & Analysis Results & Analysis

Picture of Nanoparticle Picture of Nanoparticle

Au particle Au particle Au Ag particle Au Ag particle

Ag particle Ag particle Ag particle with no BSPP Ag particle with no BSPP

The picture of the Rose window in the Notre Dame cathedral

Paris.

Single nanoparticles of Au, Ag, Au-Ag, Au with no BSPP of ~20nm size were detected

The plasmon band is very sensitive to the exact shape of the particles

Future Research : change the light path in the microscope so that a spectrometer can be used

to measure the plasmon band ( record spectra of individual spectra)

Single nanoparticles of Au, Ag, Au-Ag, Au with no BSPP of ~20nm size were detected

The plasmon band is very sensitive to the exact shape of the particles

Future Research : change the light path in the microscope so that a spectrometer can be used

to measure the plasmon band ( record spectra of individual spectra)

The spectrometer that was used to find the plasmon of each particles

Inside of the spectrometer

that shows the light path. Conclusions Conclusions

Different samples showed different colors . Au particles were

expected to be brown. However, they contained more red and

yellow particles. The actual colors of particles are different

probably because different shapes and size present in the samples.

Especially for Ag triangle, there were many different colors.

This is one reason nanoparticles need to be studied using a

microscope.

Different samples showed different colors . Au particles were

expected to be brown. However, they contained more red and

yellow particles. The actual colors of particles are different

probably because different shapes and size present in the samples.

Especially for Ag triangle, there were many different colors.

This is one reason nanoparticles need to be studied using a

microscope.

Discussion Discussion

Solutions ( Ag, Au, Ag with no BSPP), Au: Ag)Solutions ( Ag, Au, Ag with no BSPP), Au: Ag)