Comparison of Methods and Achievable Uncertainties for the Relative and Absolute Measurement of Photoluminescence Quantum Yields

Abstract

The photoluminescence quantum yield (Φ(f)) that presents a direct measure for the efficiency of the conversion of absorbed photons into emitted photons is one of the spectroscopic key parameters of functional fluorophores. It determines the suitability of such materials for applications in, for example, (bio)analysis, biosensing, and fluorescence imaging as well as as active components in optical devices. The reborn interest in accurate Φ(f) measurements in conjunction with the controversial reliability of reported Φ(f) values of many common organic dyes encouraged us to compare two relative and one absolute fluorometric method for the determination of the fluorescence quantum yields of quinine sulfate dihydrate, coumarin 153, fluorescein, rhodamine 6G, and rhodamine 101. The relative methods include the use of a chain of Φ(f) transfer standards consisting of several "standard dye" versus "reference dye" pairs linked to a golden Φ(f) standard that covers the ultraviolet and visible spectral region, and the use of different excitation wavelengths for standard and sample, respectively. Based upon these measurements and the calibration of the instruments employed, complete uncertainty budgets for the resulting Φ(f) values are derived for each method, thereby providing evaluated standard operation procedures for Φ(f) measurements and, simultaneously, a set of assessed Φ(f) standards.

Quantification of Anisotropy-Related Uncertainties in Relative Photoluminescence Quantum Yield Measurements of Nanomaterials – Semiconductor Quantum Dots and Rods

“…[32] All emission spectra were corrected for emission from the solvent and dark counts from the detector (blank correction) and for instrument-specific contributions (emission correction), as described elsewhere. [33] The PL values of all samples were calculated relatively to rhodamine 101 (Rh101, PL = 0.915 [9]) employing the formula of Demas and Crosby, see Equation (3) [34]:…”

Determination of the photoluminescence quantum yield of dilute dye solutions (IUPAC Technical Report)

“…The direct method measures the emitted photons, whereas the calorimetric method measures, directly or indirectly, the increase in temperature in the sample [16]. Since Vavilov first introduced both the term "fluorescence yield" and a method for its determination for fluorescent organic dyes in liquid solution [17,18], numerous publications have appeared that deal with measurements of fluorescence quantum yields and/or suggested or recommended quantum yield standards [1, 16,19,[34][35][36][37][38][39][40]. However, despite the obvious and ever increasing importance of Φ f , at present, there are only very few overall accepted recommendations for the comparatively simple determination of this quantity even for transparent, dilute solutions available [28,30,36,40] as well as only very few reports on achievable measurement uncertainties [36,38,41,42].…”

“…Since Vavilov first introduced both the term "fluorescence yield" and a method for its determination for fluorescent organic dyes in liquid solution [17,18], numerous publications have appeared that deal with measurements of fluorescence quantum yields and/or suggested or recommended quantum yield standards [1, 16,19,[34][35][36][37][38][39][40]. However, despite the obvious and ever increasing importance of Φ f , at present, there are only very few overall accepted recommendations for the comparatively simple determination of this quantity even for transparent, dilute solutions available [28,30,36,40] as well as only very few reports on achievable measurement uncertainties [36,38,41,42]. This includes a recent assessment of measurement uncertainties related to each step required for the relative measurement of Φ f employing similar excitation wavelengths for sample and standard, a dye transfer chain approach, and the use of different excitation wavelengths in conjunction with an excitation correction as well as absolute measurements of Φ f with two different integrating spheres, a custom-made and a commercial setup [36,38,42].…”

“…However, despite the obvious and ever increasing importance of Φ f , at present, there are only very few overall accepted recommendations for the comparatively simple determination of this quantity even for transparent, dilute solutions available [28,30,36,40] as well as only very few reports on achievable measurement uncertainties [36,38,41,42]. This includes a recent assessment of measurement uncertainties related to each step required for the relative measurement of Φ f employing similar excitation wavelengths for sample and standard, a dye transfer chain approach, and the use of different excitation wavelengths in conjunction with an excitation correction as well as absolute measurements of Φ f with two different integrating spheres, a custom-made and a commercial setup [36,38,42]. In addition, a few application notes have been provided by instrument manufactures [43], yet no approved guidelines or technical notes exist at present.…”

“…Front face measurements and the measurement of Φ f values of scattering solutions are beyond the scope of this document. This holds also true for other methods for the determination of Φ f including calorimetric approaches that have been recently reviewed [16], and integrating sphere-based techniques, which enable measurements of scattering samples and yield absolute fluorescence quantum yields [36,38,40,44,45,47]. The determination of Φ f of solid samples and films is detailed in [15].…”