Previous Experimentation on Quantum Dots

From here the software is used to record an emission Spectra that looks something like the image below.

Another possible experiment is through the use of various glass filters, each filter having a different size quantum dot. By find the absorption spectra one can determine the quantum dot band gaps and radii. The experiment would look something like the image below.

The results from each filter should look like the following image here.

A very useful equation in determining the size of a quantum dot can be seen below.

General view of Using Spectroscopy with Quantum Dots - Lab Overview (Buffalo.edu)

To record the spectra, samples each with a different nanocrystal radius can be used. From these data, you can determine the average nanocrystal radius as well as its range of values.

Finally, you can record the emission spectrum for just the light source (light emitting diode LED) which you use to excite the Quantum Dot spectra

The spectrometer can be used to record the absorption spectra from CdSe nanocrystals also known as “quantum dots.” 
The QDs will be in the form of glass filters each with a different nanocrystal radius. 

"These filters aren’t just painted or colored glass, but actually quantum dots inside of the glass itself."

The spectrometer captures a transmission spectrum similar to the one shown below;

Expected result from the SEM for Quantum Dots;

http://www.physics.buffalo.edu/faculty/APetrou/QD_Intro.pdf

Brass Sample

Brass Sample

Here is a blog that consists our data about the Brass Sample taken under the Scanning Electron Microscope (SEM). We obtained a Brass Sample from Metal Supermarkets located in Albany, NY. They were nice enough to donate some metal samples to us so we could conduct our research on various metal samples under the SEM. Below is the data we collected:




Owner/Manager - Diane H Watters
1054 Broadway, Albany, NY 12204
(518) 435-0024
dwatters@metalsupermarkets.com

Data Number: SAInTCentr

Magnification: 2300

Accelerating Voltage: 30000 Volt

Emission Current: 84000 nA

Working Distance: 12400 um

Above we can see the spectrum acquired by the Brass Sample.

We found that Brass consists of Zinc(Zn), Copper(Cu), and Aluminium(Al). The Zinc peaked at 1.015 keV, 8.627 keV, and 9.575 keV. The Copper peaked at 0.933 keV, 8.046 keV, and 8.908 keV. The Aluminium only peaked at 1.489 keV.

 Below is the data we collected using the HD Prime X-Ray Flourescence (XRF) Analyzer:

Aluminium Sample

Aluminium Sample

Here is a blog that consists our data about the Aluminium Sample taken under the Scanning Electron Microscope (SEM). For this sample, we studied the aluminium from the stages we use to place most of our other samples on. When we study other samples that we place on the stage, most of the time aluminium shows up on the spectrum for other samples. This is most likely because of the aluminium stage that we place our samples on. For this data collection we zoomed in on just the aluminium stage itself and took data from there. Below is the data we collected:

Data Number: SAInTCentr

Magnification: 2300

Accelerating Voltage: 30000 Volt

Emission Current: 87000 nA

Working Distance: 18200 um

As we expected, this sample mostly consists of the element Aluminium. There were however some Magnesium traces in this particular sample. 

Above we can see the spectrum obtained for the Aluminium Sample. 

We found the Aluminium(Al) to peak at 1.496 kev, and the Magnesium(Mg) to peak at 1.255 keV.

 Below is the data we collected using the HD Prime X-Ray Flourescence (XRF) Analyzer:

Cary 100 Spectrometer

Informational Video-https://www.youtube.com/watch?v=wxrAELeXlek

Literature about the UV-Vis Cary 100 Spectrometer-http://www.labcompare.com/106-Spectrophotometer/1094-Cary-100-UV-Vis-Spectrophotometer/

More literature about the UV-Vis Cary 100 Spectrometer-http://www.agilent.com/cs/library/usermanuals/public/1972.pdf

Composition of Various Metals

Steel- Low-alloy steels contain different materials which have different mechanical properties superior to regular carbon steels. This results in additional elements such as nickel, chromium, and molybdenum. The total alloy content can range from 2.07% up to levels just below that of stainless steels, which contain a minimum of 10% Cr. 

Brass- Composed of Zinc and Copper in different compositions to effect properties. (May include a range of other elements including arsenic, phosphorus, aluminium, manganese, and silicon.)

Bronze- Composed of Tin and Copper in different compositions to effect properties. (May include a range of other elements including arsenic, phosphorus, aluminium, manganese, and silicon.)

Silver- May occasionally contain Silver

Stainless Steel- Same as carbon steel (regular steel), but contains a minimum of 10.5% chromium.

Possible metal sample pack

HD-Prime Notes, Data Collection

Start the HD-Prime by turning the HD-Prime box on first and then the computer.

Next we place the samples in the machine and place a plastic film over our sample to prevent contamination. Then the tube is lowered to the sample, making sure the tip is in contact with the sample, with the film still in between the tip and sample.

Now we can take data be hitting quantify, From here we input the user's name as well as label the sample we are taking. Also selecting the parameters for what we are testing and the material being tested. We were using metal so we selected metal as our material and for the testing type we would select extended measurment. this would take us 6 minutes per sample to then quantify.

To extract data goto data on HD-prime viewer, goto today's date and open the file on the HD-prime viewer software. you can then export this spectrum data onto a flashdrive. This will allow you to analyze the data on your own computer (PC only) using excel and Matlab.