Ultrafast and nonlinear spectroscopy of brilliant green-based nanoGUMBOS with enhanced near-infrared emission

Abstract

The synthesis, characterization, ultrafast dynamics, and nonlinear spectroscopy of 30 nm nanospheres of brilliant green-bis(pentafluoroethylsulfonyl)imide ([BG][BETI]) in water are reported. These thermally stable nanoparticles are derived from a group of uniform materials based on organic salts (nanoGUMBOS) that exhibit enhanced near-infrared emission compared with the molecular dye in water. The examination of ultrafast transient absorption spectroscopy results reveals that the overall excited-state relaxation lifetimes of [BG][BETI] nanoGUMBOS are longer than the brilliant green molecular dye in water due to steric hindrance of the torsional degrees of freedom of the phenyl rings around the central carbon. Furthermore, the second harmonic generation signal of [BG][BETI] nanoGUMBOS is enhanced by approximately 7 times and 23 times as compared with colloidal gold nanoparticles of the same size and the brilliant green molecular dye in water, respectively. A very clear third harmonic generation signal is observed from the [BG][BETI] nanoGUMBOS but not from either the molecular dye or the gold nanoparticles. Overall, these results show that [BG][BETI] nanoGUMBOS exhibit altered ultrafast and nonlinear spectroscopy that is beneficial for various applications including nonlinear imaging probes, biomedical imaging, and molecular sensing.

Efficient Photoinduced Energy Transfer in Porphyrin-Based Nanomaterials

“…As shown in Figure 6c, experimental data are fit with a global analysis technique using a sum of exponential functions. 17,18,55 The equation used i n t h e g l o b a l a n a l y s i s fi t is of the form…”

“…We have previously investigated the ultrafast excited-state dynamics of different types of nanoGUMBOS using transient absorption spectroscopy. , In one study, we reported observation of tunable intermolecular energy transfer in crystalline ruthenium bipyridine-–bis­(pentafluoroethylsulfonyl)­imide ([Ru­(bipy) 3 ]­[BETI] 2 ) nanoGUMBOS in colloidal suspension in water . Size-dependent relaxation dynamics were observed in these nanoGUMBOS, characterized by decay dynamics similar to the Ru­(bipy) 3 Cl 2 dye with an added relaxation pathway from intermolecular energy transfer .…”

“…This anomalous phonon trend suggests a very low coupling between electronic and phonon degrees of freedom and strong hydrophobic interactions with the aqueous solvent . In a second study, brilliant green–bis­(pentafluoroethylsulfonyl)­imide ([BG]­[BETI]) nanoGUMBOS demonstrated slower relaxation dynamics than the BG molecular dye due to the steric hindrance of the torsional degrees of freedom of the phenyl rings around the central carbon in the nanoGUMBOS environment while also displaying enhanced nonlinear optical signals . Understanding the excited-state dynamics of different porphyrin-based nanoGUMBOS is essential for the development and optimization of various optoelectronic applications.…”

Recent Progress in Synthesis and Applications of Tunable Materials and Nanomaterials Based on Organic Salts

“…T.E. Karam et al [127] . introduced thermally stable, brilliant green‐based nanoGUMBOS [BG][BETI] (BG=brilliant green) (Figure 17).…”

“…T.E. Karam et al [127] introduced thermally stable, brilliant green-based nanoGUMBOS [BG][BETI] (BG = brilliant green) ( Figure 17 MIPs (molecularly imprinted polymers) exhibited property of molecular separation and sensing while inferring of electrostatic/hydrogen bonding under aqueous medium has become a major problem. To overcome this drawback of conventional MIPs, S. Hamdan et al [128] introduced four NGMIPs (nano-GUMBOS molecular imprinted polymers) that applied in the enantiorecognition for chiral amino acids (D-and L-tryptophane) ( Table 3, Entry 15-18).…”