Absolute quantum yield measurement of powder samples

Area of Science:

• Photonic Science
• Materials Science
• Analytical Chemistry

Background:

• Fluorescence quantum yield is a critical parameter for evaluating the efficiency of fluorescent materials.
• Accurate measurement is essential for the development and quality control of illumination, organic electronics, and bio-industry probes.
• Traditional methods can be complex and time-consuming, necessitating streamlined and reliable techniques.

Purpose of the Study:

• To detail a precise methodology for measuring fluorescence quantum yield in powder samples.
• To demonstrate the application of the Hitachi F-7000 fluorescence spectrophotometer with its Quantum Yield accessory for accurate measurements.
• To highlight the importance of instrument and integrating sphere correction factors for reliable results.

Main Methods:

• Generation of instrument correction factors for excitation and emission monochromators.
• Measurement of integrating sphere correction factors to account for reflectivity.
• Direct and indirect excitation measurements of reference and sample powders.
• Calculation of corrected quantum yield and chromaticity coordinates using dedicated software.

Main Results:

• The Hitachi F-7000 system demonstrates high sensitivity (S/N ratio ≥ 800) and a wide dynamic range (6 orders of magnitude).
• Accurate measurements were achieved across a broad wavelength range (240-800 nm).
• The system successfully measured quantum yields for samples like salicylic acid (as low as 0.1) and magnesium tungstate (as high as 0.8), with sodium salicylate yielding 0.4-0.5.

Conclusions:

• The described method using the Hitachi F-7000 provides accurate and sensitive fluorescence quantum yield measurements for powder samples.
• The system's capabilities facilitate efficient evaluation and quality control in diverse scientific and industrial fields.
• Incorporating spectral response and correction factors is crucial for obtaining reliable quantum yield data.