Luminescence quantum yield determination for molecules adsorbed onto solid powdered particles.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Accurate determination of fluorescence quantum yield is crucial for various applications.
• Existing methods are often unsuitable for dyes adsorbed onto solid substrates like microcrystalline cellulose.
• Challenges include preventing luminescence from interfering with reflectance measurements.

Purpose of the Study:

• To develop a novel, broadly applicable methodology for determining the fluorescence quantum yield of dyes adsorbed onto microcrystalline cellulose.
• To adapt and improve upon existing spectroscopic methods for solid-state samples.
• To provide a simple and general procedure for luminescence quantum yield determination.

Main Methods:

• Utilized ground-state diffuse reflectance spectra obtained with and without specific filters.
• Employed cut-on filters to isolate reflectance signals and prevent detector saturation by sample luminescence.
• Developed new equations to correct for fluorescence emission and detector sensitivity, accounting for substrate effects.

Main Results:

• Successfully applied the methodology to rhodamine 101, cresyl violet, and auramine O adsorbed on microcrystalline cellulose.
• Demonstrated the effectiveness of corrected reflectance spectra in accurately measuring fluorescence quantum yield.
• Validated the method's applicability beyond the specific dyes and substrate studied.

Conclusions:

• The presented methodology offers a robust and simple approach for quantifying the fluorescence quantum yield of adsorbed dyes.
• This technique is adaptable for other probes, surfaces, and luminescence types (e.g., phosphorescence).
• It addresses a significant challenge in solid-state luminescence analysis, enhancing material characterization capabilities.