What caused the secondary peak in our photoluminescence experiment?

In summary, after performing a photoluminescence experiment on two samples of different concentration, it was observed that the sample with higher concentration had an additional secondary peak at around 400 nm. The samples, which were CdS quantum dot structures in toluene, were excited with a 325 nm 50 mW continuous wave operating Kimmon UV laser. This may be due to different size dispersions of the quantum dots QD1 and QD2. The results of the experiment are attached to this post. The reason for the secondary peak at 400 nm is still unclear and further investigation is needed.
  • #1
Septim
167
6
Greetings everyone,

We have performed a photoluminescence experiment and plotted the resultant spectra for two samples of different concentration after correcting for the response of the CCD camera and got the results that is attached to this post. My question is that in the sample with higher concentration the peak is at the same wavelength; however, we have an additional secondary peak at around 400 nm. We were not able to explain this and I would be happy to know why it was observed. Both of the samples were CdS quantum dot structures in toluen and the samples were excited with a 325 nm 50 mW continuous wave operating Kimmon UV laser.

Thanks in advance
 

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  • #2
It may be QD1 and QD2 with different size dispersions.
 

1. What is photoluminescence?

Photoluminescence is the emission of light by a material when it absorbs photons. This process occurs when a material is excited by an external energy source, such as a laser or UV light, and then re-emits that energy as light.

2. How is photoluminescence measured in an experiment?

In a photoluminescence experiment, the emitted light is usually collected and measured using a spectrometer. This instrument separates the emitted light into different wavelengths, allowing for the determination of the photoluminescence spectrum of the material.

3. What types of materials can be studied using photoluminescence?

Photoluminescence is a versatile technique that can be used to study a wide range of materials, including semiconductors, metals, organic compounds, and biological molecules. It is particularly useful for studying the electronic and optical properties of these materials.

4. What factors can affect the results of a photoluminescence experiment?

Several factors can impact the results of a photoluminescence experiment, including the purity of the sample, the excitation energy, and the temperature. Contamination, impurities, and defects in the material can also affect the photoluminescence properties.

5. What are some applications of photoluminescence in scientific research?

Photoluminescence is used in various fields of scientific research, including materials science, chemistry, physics, and engineering. It is commonly used to study the electronic and optical properties of materials, as well as for the detection and characterization of defects and impurities in materials. It also has practical applications in the development of new optoelectronic devices, such as LEDs and solar cells.

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