Sensors Stokes shift

Another important feature of fluorophores is the amount of vibrational energy lost in the excited state. The difference between emission and excitation maxima gives a readout in this respect and is referred to as the Stokes shift. In many sensors, a small Stokes shift is unfavorable for FRET ratio measurements due to overlap of emission spectra. 

In developing OLED-based oxygen and glucose sensors, oxygen-sensitive Ru, Pt, and Pd-based dyes, with large Stokes shifts (>100nm), were used. However, the rhodamine-based dye has a Stokes shift of only 20nm. As... 

In other instances, where analyte-sensitive dyes with a narrower Stokes shift are utilized, the contribution of the long-wavelength EL tail to the background can be large, reducing the detection sensitivity and deteriorating the LOD. An example for that behavior is that of a sensor for anthrax lethal factor (LF), which is one of the three proteins of the anthrax toxin secreted by the live Bacillus anthracis bacterium. The development of a compact, field-deployable, and low-cost sensor for prompt, on-site detection of... 

In general, lanthanide-based sensors have strongly attracted the attention of the scientific community worldwide for some decades due to their unique and outstanding photophysical characteristics such as long emission lifetimes, very narrow emission bands and large Stoke shifts. These spectroscopic features allow time resolved detection that is the most elegant way to clear measurements from background fluorescence with a consequent remarkable sensitivity enhancement. As already mentioned in Sect. 3.1.1.1 [120], DPA or better calcium dipicolinate... 

Pt(ll) porphyrins are interesting dyes for optical sensor applications because they have long excited state lifetimes, large Stokes shifts, and room temperature phosphorescence [81, 113]. Fluorinated derivatives of Pt(ll) porphyrins show improved hydrophobicity and enhanced oxidative stability thus, they have been utilized as luminescent dyes. In addition, as was described previously, the use of pentafluorophenyl groups on the porphyrin meso-position has permitted the direct... 

Scheme 38 Schematic representation of sensor 4,1 (phe amhrene-pyrem) with bound D-glu-cose (depicted as a red ellipse). D-Glucose allows a revival of fluorescence emission from the LE pyrene fluorophore when pyrene is excited directly. Excitation and emission wavelengths are illustrated in blue and red, respectively. The colours are used to depict the Stokes shift of the system rather than the actual colour of the light.

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