CSS offers a catalogue of dichroic dyes with different properties for different optical applications. We also offer polymerisable molecules for crosslinking with reactive mesogens.
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Dichroic Dyes Explained
Dichroic Dyes are a special class of rod-shaped dye used in Liquid Crystal (LC) systems, that align with the liquid crystal molecules and only absorb light in one orientation. Dichroic Dyes in Liquid Crystals are often referred to as Guest-Host systems, the LC acting as the Host to the Guest dye.
When an electric field is applied, the LC and Dichroic Dye align in the same direction as the incident light, which is the dye’s non-absorbing direction. Therefore, the light passes though unchanged with no absorbance by the dye.
With no voltage applied, the LC and Dichroic Dyes dis-align, now allowing the dyes to absorb the incoming light. As the light passes through the system, part is absorbed by the dye, and coloured light exits.
Mixing of several colours of Dichroic Dyes to create a black dichroic dye leads to a total light reduction between the incoming and exiting light, giving a light-dimming effect. This effect is particularly useful for switchable, dimmable glass or polymer-film.
For further reading, we recommend Dr John Moore’s excellent open-access publication, from which the graphics above were reproduced (with permission Link).
CSS’s Range of Dichroic Dyes
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Black Dichroic Dyes | 400 – 700 nm |
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UVA Dichroic Dyes | 350 – 400 nm |
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Yellow Dichroic Dyes | 400 – 450 nm |
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Orange Dichroic Dyes | 450 – 500 nm |
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Red Dichroic Dyes | 500 – 530 nm |
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Magenta Dichroic Dyes | 530 – 550 nm |
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Purple Dichroic Dyes | 550 – 590 nm |
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Blue Dichroic Dyes | 590 – 700 nm |
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NIR Dichroic Dyes | 700 – 1000 nm |
NIR Dichroic Dyes
Dye Name: DDIR855
Item Code: 110001
CAS Number: 74099-49-3
Dye Class: Nickel dithiolene
Lambda max / FWHM / Solvent: 899 nm / 200 nm / Benzonitrile
Colour: Colourless to very pale green
Dichroic Ratio / LC / Reference: DR = 7 / Merck E7 / K.L. Marshall
Polymerisable group: Non-polymerisable