Absolute “Two measurement” vs Relative quantum yield measurement techniques:An experimental analysis

In this work, we report a comparative study of quantum yield (QY) or quantum efficiency (QE) measurement using relative and absolute “two measurement” techniques for the high and low quantum efficiency materials to explore the measurement techniques for a wide range of applicability. We have experimentally determined the relative quantum efficiency of rhodamine 6G (a highly luminescent material) at 490 nm excitation wavelength using cuvette holder and compared the result with absolute quantum efficiency obtained using integrating sphere at the same excitation wavelength. Furthermore, to do the comparative study with low luminescent materials, cadmium selenide (CdSe) quantum dots have been fabricated and characterized. From the analysis, we observed very less variation in quantum efficiencies obtained from above stated measurement techniques. In this paper, we are also reporting the absolute quantum efficiency of fluorescein and rhodamine 6G at an excitation wavelength of 470 nm. These quantum efficiencies may be used as a reference for the quantum yield measurement of luminescent materials.