Picosescond fluorescence lifetime standards for frequency- and time-domain fluorescence

Area of Science:

• Photochemistry
• Spectroscopy
• Materials Science

Background:

• Fluorescence lifetime measurements are crucial for various scientific disciplines.
• Developing reliable standards is essential for accurate instrument calibration and data interpretation.
• Existing standards may have limitations in quantum yield, solubility, or oxygen sensitivity.

Purpose of the Study:

• To characterize a series of dimethylamino-stilbene derivatives as potential standards for fluorescence lifetime measurements.
• To evaluate their suitability for both time-domain and frequency-domain techniques.
• To assess their performance across different experimental conditions and as components in calibration mixtures.

Main Methods:

• Synthesis and characterization of dimethylamino-stilbene derivatives.
• Measurement of quantum yields and oxygen quenching sensitivity.
• Frequency-domain fluorescence lifetime measurements up to 10 GHz.
• Characterization of single-fluorophore and two-fluorophore mixtures.

Main Results:

• Dimethylamino-stilbene derivatives exhibited good quantum yields and solubility, with minimal oxygen sensitivity.
• All compounds showed single exponential intensity decays, with lifetimes ranging from 57 to 880 ps.
• Decay times were independent of excitation and emission wavelengths.
• Two-fluorophore mixtures with twofold spaced decay times were prepared and characterized.

Conclusions:

• The characterized dimethylamino-stilbene derivatives serve as valuable standards for picosecond time-domain and gigahertz frequency-domain fluorescence lifetime instruments.
• These compounds can be used for instrument testing and as reference materials to correct for color effects.
• The developed fluorophore mixtures are useful for assessing the resolution capabilities of fluorescence lifetime instrumentation.