Phosphor conversion based LED limit......

Stephenj37826 said:

So the 4.7 umol/j is qer of roughly 3000k. This is the photon count of 3000k spectrum per joule of light output. One of two things will/is occur/ing (A we will hit a ceiling of 3.72 umol) (B the phosphorus is not simply "peeling" energy off each respective photon but rather redistributing the energy)

Can someone please clarify this for me if I'm wrong.

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PhotonFUD said:

One way to better understand the conversions is to look at the separate activities involved in isolation.

The first is the generating photons of a blue wavelength using the electron gap of the diode. That takes x amount of electrical energy to do and without any further processing produces 3.72umoles worth of radiant energy in that wavelength. Consider the 3.72umoles being a count of photons.

That photon then hits a phosphor coating absorbing it and its energy. This excites the phosphor to generate a photon of a longer wavelength, eg. red. The difference of energy between the two wavelengths mainly results in waste heat which combined from the waste heat from the first activity is dealt with by thermal management. Output using the same x amount of electrical energy produces 4.7umoles worth of radiant energy with a light using more red wavelengths.

Photon to photon, a lower wavelength has more energy than a higher wavelength. It takes less energy to create a photon with a higher wavelength. The end output is that x amount of electricity can produce 3.72umoles of blue photons or 4.7umoles of 3000k photons. Since all we care about is photons, this represents a 26% increase in photon count.

Photosynthesis uses 700nm photons; plants will absorb shorter wavelengths and condition the photon by reducing the energy to increase the wavelength to 700nm. This conversion requires resources for the process and also to manage the waste heat energy. The closer to 700nm each absorbed photon is, the less resources the plant has to use.

The led phosphor conversion process performs a similar function to that of the plant photon conditioning process. Providing as many photons close to the 700nm wavelength is how we can best help the photosynthetic process.

Hope that helps.

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MeJuana said:

This is a sub interest of mine, not light but energy. Two photons can be absorbed then released into one at a higher energy rating. So no laws of psychics are broken we are carefully creating an environment with a favorable likely outcome.

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robincnn said:

https://en.wikipedia.org/wiki/Jablonski_diagram

I think the way it works is that a high energy (hv) blue photon hits and electron and pushes it to higher energy state. Now some of this energy (E) is lost in molecular vibrations what i do not completely understand. So now electron jumps back to default state and emits a lower energy (hv-E) red/yellow photon.
So the key here is 1 Blue photon converts to 1 Red or yellow Photon. The energy difference is lost as Stokes shift loss
It cannot take 2 blue photons and then give 3 red photons. It does not work like that.

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Stephenj37826 said:

There is no recombination of energy between 2 separate photons. Whatever energy lost is lost......Each photons reaction is it's own subsystem.

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PhotonFUD said:

Correct. Each reaction takes place in isolation. The photon output of the first reaction provides the energy for the second reaction. Photons have duality properties of both waves and particles and are emitted during transition to a lower energy level. The recombination of energy as you call it is done in the conversion properties of the phosphor.

For simplicity sake, say it may take the equivalent energy of 4 blue photons for the led phosphor to generate 5 red photons and some amount of waste heat. That represents an increase of 25% in photons so it is actually close to the blue vs 3000k comparison. The 4 blue photons would have a total of more energy than the 5 red photons.

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Stephenj37826 said:

Right you will never have a higher photon count than what you started with at the blue diodes.

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PhotonFUD said:

Incorrect. The generation of the second photon is independent of the first. The energy from the first photon is absorbed and then that energy is used to generate (emit is the correct term) a photon in the phosphor reaction.

Photon count is primarily determined by energy. Photons are released when atoms and molecules transition to a lower energy state. Putting energy in transitions to a higher energy state.

Having the properties of waves and particles photons can be tricky.

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Stephenj37826 said:

Please point us to studies showing this occuring.

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