What Is the Best Method to Fit Time-Resolved Data? A Comparison of the Residual Minimization and the Maximum Likelihood Techniques As Applied to Experimental Time-Correlated, Single-Photon Counting Data

Santra, Kalyan; Zhan, Jinchun; Song, Xueyu; Smith, Emily A.; Vaswani, Namrata; Petrich, Jacob W.

doi:10.1021/acs.jpcb.6b00154

Cited by 30 publications

(49 citation statements)

References 44 publications

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“…As above, the fluorescence decay curves recorded for BAB(H) could be analysed satisfactorily in terms of mono‐exponential fits in non‐polar (i.e., ϵ s <8) solvents. However, with increasing solvent polarity the quality of the exponential fit was seen to worsen; this judgement was based on the reduced chi‐squared parameters ( χ 2 in Table ) and the randomness of the weighted residuals. Furthermore, the radiative rate constant ( k rad = Φ F / τ S ) adopts a strong dependence on solvent polarity that does not seem justified .…”

Section: Resultsmentioning

confidence: 99%

Solvent‐Driven Conformational Exchange for Amide‐Linked Bichromophoric BODIPY Derivatives

Thakare

Stachelek

Mula

et al. 2016

Chemistry A European J

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The fluorescence lifetime and quantum yield are seen to depend in an unexpected manner on the nature of the solvent for a pair of tripartite molecules composed of two identical boron dipyrromethene (BODIPY) residues attached to a 1,10-phenanthroline core. A key feature of these molecular architectures concerns the presence of an amide linkage that connects the BODIPY dye to the heterocyclic platform. The secondary amide derivative is more sensitive to environmental change than is the corresponding tertiary amide. In general, increasing solvent polarity, as measured by the static dielectric constant, above a critical threshold tends to reduce fluorescence but certain hydrogen bond accepting solvents exhibit anomolous behaviour. Fluorescence quenching is believed to arise from light-induced charge transfer between the two BODIPY dyes, but thermodynamic arguments alone do not explain the experimental findings. Molecular modelling is used to argue that the conformation changes in strongly polar media in such a way as to facilitate improved rates of light-induced charge transfer. These solvent-induced changes, however, differ remarkably for the two types of amide.

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Section: Resultsmentioning

confidence: 99%

Solvent‐Driven Conformational Exchange for Amide‐Linked Bichromophoric BODIPY Derivatives

Thakare

Stachelek

Mula

et al. 2016

Chemistry A European J

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“…Full information on the categories and mathematical treatment is available in Supporting Information, with results shown in Figure S3. [71] The results of the ON-OFF fitting are shown in Figure 3, and the fit parameters are listed in Table S1. The CsPbBr 3 , CsPbI 3 , and CsPbI 3 -MeOAc nanocrystals were on for 87 %, 97 %, and 99 % of the total analysis time, respectively.…”

Section: Articlesmentioning

confidence: 99%

Unveiling the Photo‐ and Thermal‐Stability of Cesium Lead Halide Perovskite Nanocrystals

et al. 2019

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Lead halide perovskites possess unique characteristics that are well-suited for optoelectronic and energy capture devices, however, concerns about their long-term stability remain. Limited stability is often linked to the methylammonium cation, and all-inorganic CsPbX 3 (X=Cl, Br, I) perovskite nanocrystals have been reported with improved stability. In this work, the photostability and thermal stability properties of CsPbX 3 (X=Cl, Br, I) nanocrystals were investigated by means of electron microscopy, X-ray diffraction, thermogravimetric analysis coupled with FTIR (TGA-FTIR), ensemble and single particle spectral characterization. CsPbBr 3 was found to be stable under 1-sun illumination for 16 h in ambient conditions, although single crystal luminescence analysis after illumination using a solar simulator indicates that the luminescence states are changing over time. CsPbBr 3 was also stable to heating to 250°C. Large CsPbI 3 crystals (34 � 5 nm) were shown to be the least stable composition under the same conditions as both XRD reflections and Raman bands diminish under irradiation; and with heating the γ (black) phase reverts to the nonluminescent δ phase. Smaller CsPbI 3 nanocrystals (14 � 2 nm) purified by a different washing strategy exhibited improved photostability with no evidence of crystal growth but were still thermally unstable. Both CsPbCl 3 and CsPbBr 3 show crystal growth under irradiation or heat, likely with a preferential orientation based on XRD patterns. TGA-FTIR revealed nanocrystal mass loss was only from liberation and subsequent degradation of surface ligands. Encapsulation or other protective strategies should be employed for long-term stability of these materials under conditions of high irradiance or temperature.[a] B.

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“…[3][4][5][6] Typically, in a TCSPC experiment, a fluorescence lifetime is determined by acquiring a histogram of arrival time differences between an excitation pulse and the pulse resulting from a detected photon. As we have noted, 3,4 when a histogram of sufficient quality cannot be obtained to provide a good fit by means of minimizing the residuals (RM) between the experimental data and a given functional form, the maximum likelihood (ML) technique is particularly effective, namely when the total number of counts is very low. 3 As we have shown in the case of rose bengal, ML retrieved the correct mean lifetime to within 2% of the accepted value with total counts as low as 20; and it retrieved the correct mean lifetime with less than 10% standard deviation with total counts as low as 200.…”

Section: Introductionmentioning

confidence: 99%

Photon Counting Data Analysis: Application of the Maximum Likelihood and Related Methods for the Determination of Lifetimes in Mixtures of Rose Bengal and Rhodamine B

et al. 2016

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It is often convenient to know the minimum amount of data needed to obtain a result of desired accuracy and precision. It is a necessity in the case of subdiffraction-limited microscopies, such as stimulated emission depletion (STED) microscopy, owing to the limited sample volumes and the extreme sensitivity of the samples to photobleaching and photodamage. We present a detailed comparison of probability-based techniques (the maximum likelihood method and methods based on the binomial and the Poisson distributions) with residual minimization-based techniques for retrieving the fluorescence decay parameters for various two-fluorophore mixtures, as a function of the total number of photon counts, in time-correlated, single-photon counting experiments. The probability-based techniques proved to be the most robust (insensitive to initial values) in retrieving the target parameters and, in fact, performed equivalently to 2-3 significant figures. This is to be expected, as we demonstrate that the three methods are fundamentally related. Furthermore, methods based on the Poisson and binomial distributions have the desirable feature of providing a bin-by-bin analysis of a single fluorescence decay trace, which thus permits statistics to be acquired using only the one trace not only for the mean and median values of the fluorescence decay parameters but also for the associated standard deviations. These probability-based methods lend themselves well to the analysis of the sparse data sets that are encountered in subdiffraction-limited microscopies. Disciplines Chemistry | Physical Chemistry CommentsThis document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication as Santra, Kalyan, Emily A. Smith, Jacob W. Petrich, and Xueyu Song. ABSTRACTIt is often convenient to know the minimum amount of data needed in order to obtain a result of desired accuracy and precision. It is a necessity in the case of subdiffraction-limited microscopies, such as stimulated emission depletion (STED) microscopy, owing to the limited sample volumes and the extreme sensitivity of the samples to photobleaching and photodamage.We present a detailed comparison of probability-based techniques (the maximum likelihood method and methods based on the binomial and the Poisson distributions) with residual minimization-based techniques for retrieving the fluorescence decay parameters for various twofluorophore mixtures, as a function of the total number of photon counts, in time-correlated, singlephoton counting experiments. The probability-based techniques proved to be the most robust (insensitive to initial values) in retrieving the target parameters and, in fact, performed equivalently to 2-3 significant figures. This is to be expected, as we demonstrate that the three methods are fundamentally related. Furthermore, methods based on the Poisson and binomial distributions have the desirable feature of providing a bin-by-bin analysis of a single fluorescence decay trace, which thus permits statistic...

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What Is the Best Method to Fit Time-Resolved Data? A Comparison of the Residual Minimization and the Maximum Likelihood Techniques As Applied to Experimental Time-Correlated, Single-Photon Counting Data

Cited by 30 publications

References 44 publications

Solvent‐Driven Conformational Exchange for Amide‐Linked Bichromophoric BODIPY Derivatives

Solvent‐Driven Conformational Exchange for Amide‐Linked Bichromophoric BODIPY Derivatives

Unveiling the Photo‐ and Thermal‐Stability of Cesium Lead Halide Perovskite Nanocrystals

Photon Counting Data Analysis: Application of the Maximum Likelihood and Related Methods for the Determination of Lifetimes in Mixtures of Rose Bengal and Rhodamine B

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