The reason I say simpler organic, is I’m aware if you had an organic that can fluoresce only, or phosphoresce only, you can combine them via some alkyl chain, and for most of the time, the new compound does both.
For fluorescence, you have to decide what wavelength of excitation and emission you require. For organic fluorophores, the larger the molecule, the longer the wavelength of excitation, as a rule-of-thumb. A good place to find out about organic fluorophores is the Molecular Probes Handbook at the Thermo-Fisher Scientific web site.
You can also observe fluorescence from lanthanide ions (e.g., europium, terbium) when they are chelated in organic molecules. The fluorescence lifetime of these ions can be much longer than that of the purely organic fluorophores.
Don't most fluorescence emissions are just a few nm apart in the Stokes direction? Like violet to red is too far, but violet to blue?
Large Stokes shifts (difference between excitation and emission peak wavelengths) of 100-150 nm occur for some organic compounds with UV excitation. For organic fluorophores with longer wavelength excitation, smaller Stokes shifts are usual. However, it is not necessary to use the peak excitation and emission wavelengths. At the cost of reduced fluorescence intensity, excitation at a shorter wavelength than the peak and emission measurement at a longer wavelength than the peak can be used in combination with a suitable optical filter to prevent crosstalk. Furthermore, the lanthanide chelates can provide very large Stokes shifts (https://tools.thermofisher.com/content/sfs/manuals/O-062132-r1%20US%200405.pdf)
Okay, are you aware of any fluorescence/phosphorescence in the IR. As in absorb near-IR and emit deep-IR, or absorb IR and emit microwaves? Can these be organic conjugated compounds? Thanks.
There are near-IR organic fluorescent dyes.
https://www.lumiprobe.com/c/nir-infrared-dyes
https://biotium.com/technology/cf-dyes/nir-cf-dyes/
Wow, so complex compounds hm.
Okay can there by fluorescence/phosphorescence for visible light? Like shine violet light, and emit red light? So I should say, phosphorescence only.
The chelated lanthanide fluorophores are excited in the near UV and emit at long visible wavelengths. Their excited state lifetimes are long for fluorophores, up to ~ 1 msec, but not as long as the lifetimes of phosphorescent compounds such as certain mineral salts. The long lifetime allows time gating between excitation and detection of fluorescence emission, which greatly reduces background fluorescence from organic fluorophores, which have nsec lifetimes.
Article Lanthanide-Based Optical Probes of Biological Systems
Hey Adam I think this is my last question, both fluorescence and phosphorescence are measured in half-lifes right? So a fluorescence can be 1 ms, and phosphorescence be 10 s. Then it starts half-lifing, rather than completely shut down? So it is possible, for a stronger fluorescence, to be brighter than a phosphorescent, at 1 minute after turning off the lights?
I wonder what could be a good phosphorescent to buy besides benzophenone.
It's doubtful that there would be measurable fluorescence after 1 minute without illumination of a fluorescent substance, but there could easily be phosphorescence 1 minute after illuminating a phosphorescent substance.
Erythrosin is a phosphorescent compound.
https://pubmed.ncbi.nlm.nih.gov/9796431/
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