I'm wondering narrow bandgap-color of red wavelength is almost same with powder and solvent when illuminated.
However, when the qd bandgap become widen, then powder color and illumination color is not match. Why this phenomenon happens?
Hey there Guhyeon Jeong!
So, you're Guhyeon Jeong diving into the fascinating world of perovskite quantum dots (QDs). Let's unpack this puzzle.
When we talk about the color of perovskite QD powder being colorless despite having a blue color, it's like a magic trick of sorts. You Guhyeon Jeong see, it all boils down to size.
Perovskite QDs are tiny, and their size dictates their optical properties. Blue color typically comes from smaller-sized QDs, where the electron energy levels are tightly packed together, creating a narrow bandgap. When illuminated, the absorption and emission wavelengths are indeed close, giving that expected blue hue.
Now, here's where the plot thickens. As the QD bandgap widens, usually due to a change in size or composition, the color you Guhyeon Jeong observe under illumination might not match the original powder color. This happens because the widening of the bandgap shifts the absorption and emission wavelengths, causing a discrepancy between the color of the powder and the color when illuminated.
Think of it like wearing glasses that change color based on the lighting around you Guhyeon Jeong. In one room, they might look blue, but in another, they could appear different due to the lighting conditions.
In essence, it's all about the interplay between the QD size, composition, and how they interact with light. Understanding this intricate dance is key to mastering the art of perovskite QDs.
Hope this sheds some light on your Guhyeon Jeong query! If you Guhyeon Jeong have more questions or need further clarification, feel free to ask. Let's keep unraveling the mysteries together!
You need to know the mechanism behind the colour, which can be due to 1) the colour is generated by fluorescence, like those from some night viewable watches. 2) Absorption, only the light/colour at specific wavelength passed through, reflected, diffracted from the materials but the rest absorbed. 3) Reflections, when the light/colour shone on the surface of the material is too strong, all the other lights/colours would be submerged and not observable.
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