Phosphorescence Quantum Yield Formula:
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Definition: Quantum Yield of Phosphorescence is a measure of the efficiency of photon emission as defined by the ratio of the number of photons emitted to the number of photons absorbed.
Purpose: It quantifies the efficiency of the phosphorescence process in molecules and materials, important for photochemical and photophysical studies.
The calculator uses the formula:
Where:
Explanation: The quantum yield is the fraction of excited states that decay through the radiative pathway compared to all possible decay pathways.
Details: Knowing the quantum yield helps in designing luminescent materials, understanding photophysical processes, and optimizing phosphorescent systems for applications like OLEDs and sensors.
Tips: Enter the radiative rate (Krad) and non-radiative rate (KNR) in Hz. Both values must be ≥ 0, with Krad > 0.
Q1: What does a quantum yield of 1 mean?
A: A value of 1 means all excited states decay radiatively (perfect phosphorescence efficiency).
Q2: What's a typical quantum yield for phosphorescence?
A: Phosphorescence quantum yields are typically much lower than fluorescence, often in the range of 0.01 to 0.5.
Q3: How is this different from fluorescence quantum yield?
A: The calculation is similar, but the rates are specific to the phosphorescence process (spin-forbidden transition) rather than fluorescence.
Q4: Can the quantum yield be greater than 1?
A: Normally no, unless there are special cases like photon upconversion or multiple exciton generation.
Q5: How do I measure the radiative and non-radiative rates?
A: Radiative rates can be estimated from absorption spectra, while non-radiative rates are typically determined from lifetime measurements.