Metal-enhanced fluorescence and excited state dynamics of carotenoids in thin polymer films

Abstract

Metal-enhanced fluorescence of carotenoids, all- trans -β-carotene and 8′-apo-β-carotene-8′-al dispersed in thin layers of polystyrene and polyethylene glycol were investigated by time-resolved fluorescence spectroscopy. The weak emission signals of carotenoids in polymer films were increased by 4–40 times in the presence of a silver island film and the emission lifetimes of both carotenoids were measured as significantly shortened. The energy transfer from the intermediate states of carotenoids to the silver islands and the subsequent surface plasmon coupled emission were proposed for the mechanisms of metal-enhanced fluorescence. The fluorescence enhancements of carotenoids in the polymer films were also investigated statistically over a wide area of the silver island films.

Twisted Intramolecular Charge Transfer State of a “Push-Pull” Emitter

“…Steady-state absorption spectra were measured in a UV/Vis absorption spectrometer (Scinco S3100, Scinco, Seoul, Korea) and the emission spectra were measured in a home-built time-correlated single-photon counting (TCSPC) setup based on a TCSPC module (Picoharp 300, PicoQuant, Berlin, Germany) [64,65]. Fluorescence signals from the excitation of a picosecond diode laser (P-C-405, PicoQuant) at 405 nm were filtered by a long-pass filter (Omega Optical, Brattleboro, VT, USA) at 442 nm and collected by a photomultiplier tube detector (PMA 192, PicoQuant) attached to a monochromator (Cornerstone 260, Newport, Irvine, CA, USA).…”

Femtomolar Detection of Spermidine Using Au Decorated SiO2 Nanohybrid on Plasmon-Coupled Extended Cavity Nanointerface: A Smartphone-Based Fluorescence Dequenching Approach

“…Upon illumination of metal NPs at plasmon absorption frequencies large electromagnetic (EM)-near field intensities are generated, which in turn increases the excitation rate of proximal luminophores. Over and above this, the scattering mode of NPs have direct effect on emission intensity and is called as induced-plasmon effect of MEF . As a result, fluorescent molecules attain better photostability with reduced lifetimes and inflated radiative decay rates.…”

Twisted intramolecular charge transfer of nitroaromatic push–pull chromophores

“…The details of the transient absorption setup based on a 1 kHz Ti:sapphire regenerative amplifier were available elshwhere 41 , 94 . The actinic pulses at 403 nm (~ 50 nJ/pulse) were generated by SHG in a 0.1 mm thick BBO crystal (A-star photonics, Fuzhou, China) and compressed by a pair of chirped mirrors (− 30 ± 10 fs 2 group delay dispersion; Layertec GmbH).…”