The following questions refer to Quantum Dot samples (CdSe). We measured absorbance with a spectrophotometer. 1....

The following questions refer to Quantum Dot samples (CdSe). We measured absorbance with a spectrophotometer.

1. Why does a wavelength of 400 nm excitation work for all emission samples?

2. Can you use other excitation wave length other than 400 nm? Why or why not?

3. Why does the UV lamp work well for quantum dots excitation in this experiment?

4. Your explanation of emission spectra in connection to the quantum particle-in-a-box model.

Expert Solution

Spectrophotometers are designed to transmit light of narrow wavelength ranges. A given compound will not absorb all wavelengths equally–that’s why things are different colors (some compounds absorb only wavelengths outside of the visible light spectrum, and that’s why there are colorless solutions like water).

Visible light is composed of wavelengths from 400 to 700 nm (nanometers). When visible light passes through a colored solution, some wavelengths are transmitted and others are absorbed. You see the color of the transmitted wavelengths.

1. A wavelength of 400nm works for excitation of all emssion because 400nm is the apt range of visible region. The wavelength of 400nm is easily absorbed and shows light.

2. Yes, we can use excitation wavelength other than 400nm but it should only vary between 400nm - 700nm because this is the feasible range of visible region.

queen_honey_blossom answered 2 years ago

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The following questions refer to Quantum Dot samples (CdSe). We measured absorbance with a spectrophotometer. 1....

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