Is the Quantum Yield Spectrum for photoluminescence, internal or external quantum yield

  • 10 November 2020
  • 1 reply

Dear Sir/Madam,

I am working with OpticStudio to analyze photoluminescence of my design. I noticed that we are required to build the Quantum Yield Spectrum for photoluminescence simulation. Just want to verify with you what data are we supposed to use for the Quantum Yield spectrum, the external quantum yield data or the internal quantum yield data?

Based on my understanding, the internal quantum yield is defined as ratio of the number of emitted photons to the number of absorbed photons, and the external quantum yield is defined as the number of emitted photons to the number of photons impinging on the sample.

Thank you very much for your help! Hope can hear from you soon!

Best Regards,



Best answer by Csilla Timar-Fulep 10 November 2020, 10:21

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Hello Jing,

Thanks for your questions here!

The Quantum Yield spectrum is the efficiency of the down conversion process, but it does not intrinsically take into account the effect of down conversion on the ray intensity. The wavelength shift’s effect on intensity is calculated by OpticStudio by multiplying the quantum yield value by the ratio of the incident and emitted wavelengths, known as the Stokes shift:

I_Emitted = I_Incident * A * Q * (λ_Incident / λ_Emitted) = I_Absorbed * Q * (λ_Incident / λ_Emitted)

where A is the absorption coefficient and Q is the quantum efficiency. So, Q is the internal quantum yield, and A*Q would be the external.

You may find more information about the Spectrum Files and Quantum Yield in the Help files at:

The Setup Tab > Editors Group (Setup Tab) > Non-sequential Component Editor > Object Properties (non-sequential component editor) > Volume Physics > Phosphors & Fluorescence

Besides, further references can be found in the following knowledgebase articles:

Overview of photoluminescence simulation in OpticStudio

Modeling Photoluminescence in OpticStudio: A Photoluminescent Solar Concentrator

If you have any further questions, please let us know and we will be happy to help!