Laser Dyes

Abstract

The article contains sections titled: 1. Introduction 1.1. History 1.2. Dye Laser Operation 1.3. Uses 2. Classes of Dyes 2.1. Polyphenyl and Heteroaromatic Compounds 2.2. Stilbenes 2.3. Coumarins 2.4. Xanthene Dyes 2.5. Pyrromethene Dyes 2.6. Methine Dyes 2.7. Oxazine Dyes 3. Acknowledgement

Revisiting the Laser Dye Styryl-13 As a Reference Near-Infrared Fluorophore: Implications for the Photoluminescence Quantum Yields of Semiconducting Single-Walled Carbon Nanotubes

“…For instance, most of them, including Styryl-13 and Styryl-20, are rare and quite expensive chemicals. Furthermore, NIR dyes are often only moderately photostable . Whereas no photodegradation of Styryl-13 was observed in our experiments, solutions of Styryl-20 in methanol and propylene carbonate showed a significant decrease in the absorption band at ∼628 nm after absorption of only ∼10 5 photons per dye molecule (irradiation at 633 nm).…”

“…The low emission efficiency of a few percent or less can be attributed to the structural (rotational) flexibility of polymethine dyes, resulting in efficient nonradiative relaxation pathways. This correlates with a picosecond lifetime of the fluorescence. ,, The QYs of Styryl-13 and Styryl-20 increase by a factor of 2 in propylene carbonate as compared with methanol solutions (Table ). This trend has also been observed for other polymethine dyes and assigned to specific dye-solvent interactions in aprotic (propylene carbonate) versus protic (methanol) media …”

“…This approach is, however, not feasible for many commercial NIR spectrometers with a limited detection range, which are practically “blind” in the UV−visible spectral region. In this case, selected NIR emitters such as NIR laser dyes may serve as a (secondary) reference. Unfortunately, although numerous NIR dyes have been synthesized and tested for lasing in different pumping schemes (with the main interest being their tuning wavelength range, energy conversion, and photostability), their emission efficiencies have remained scarcely documented. , Calibration measurements against a “standard” fluorophore have been performed for only a few NIR dyes emitting above ∼800 nm. , Note that the QYs of NIR dyes are typically much less than unity and typically decrease along a series of compounds as emission wavelength increases.…”

Unimolecular Exciplexes by Ugi Four-Component Reaction

“…Molecular luminescence (Lakowicz, 2006; Valeur and Berberan-Santos, 2012) is a widespread phenomenon of functional organic materials (Müller and Bunz, 2007) and finds broad application in many fields of science and technology, ranging from fundamental science (luminescence spectroscopy) (Wolfbeis, 1993; Valeur and Brochon, 2012) over biophysical analytics (Chen et al, 1998; Nilsson et al, 2002; Wagenknecht, 2008; Demchenko et al, 2009; Kim and Park, 2009; Cairo et al, 2010), diagnostics (Kobayashi et al, 2010; Carter et al, 2014), and dye lasers (Thiel, 2000; Shankarling and Jarag, 2010) to sensors (Loving et al, 2010; Klymchenko, 2017; Zhang et al, 2017) and organic light-emitting diodes (OLED) (Müllen and Scherf, 2006; Park et al, 2011; Thejo Kalayani and Dhoble, 2012; Li, 2015). Besides fluorescence and phosphorescence as radiative deactivation of electronically excited singlet or triplet states, also radiative states arising from inter- or intramolecular electronic interaction, eventually by energy or electron transfer, are particularly interesting.…”