Ultrafast nonlinearoptical response of squarylium dye J-aggregates and fabrication of their LB-films

Surfactant-Induced Aggregation Patterns of Thiazole Orange: A Photophysical Study

“…These results thus support our contention that the observed spectral changes for the TO/β-CD/SDS system are mainly due to the binding interaction between the surfactant and the β-CD host, because under the present experimental conditions, the dye concentration is much lower than the SDS concentration and hence the dye will hardly get a chance to bind to β-CD. The weak binding of TO with β-CD as observed in this study is in stark contrast to the interaction of TO with another macrocyclic host, namely, calix- [4]arenesulfonate, where the presence of the sulfonate groups supports the accumulation of more than one dye molecule at the portals of the host, thus leading to the formation of TO H-aggregates. 28 These results thus, in conjunction, emphasize the key role of the electrostatic interactions in controlling the aggregation pattern of TO in the presence of SDS.…”

“…There are very few reports on fluorescent H-aggregates. 32 Recently, Lau and Heyne have observed fluorescent H-aggregates for TO in the presence of calix [4]arenesulfonate. 28 They proposed that the fluorescence could arise either due to the higher rigidity of the aggregate in comparison to the monomer or due to the presence of some twisting between the TO units (and their transition dipoles) in the aggregate.…”

Diameter-Dependent Optical Absorption and Excitation Energy Transfer from Encapsulated Dye Molecules toward Single-Walled Carbon Nanotubes

“…Thus, the measured rates of SQ excited state decay pathways can be used as a second means to estimate ϕ EET : where k EET is the rate coefficient for EET and the denominator sums all rate coefficients for decay from the encapsulated SQ excited state, including EET ( Figure 3 d). If we assume that the dominant decay pathway(s) competing against EET do not change for SQ molecules upon encapsulation (although decay times can change upon aggregation 38 , 39 ), then the 2.1 ns lifetime of free SQ molecules in toluene with respect to the GSB recovery time constant of encapsulated SQ molecules ( i.e. , τ = 205 fs) results in ϕ EET ≅ 99.99%.…”

Kinetics and mechanism of sodium (Z)-3-(5-chloro-2-((5-chloro-3-(3-sulfonatopropyl) benzothiazol-2(3H)-ylidene)methyl)benzo-thiazol-3-ium-3-yl)propane-1-sulfonate adsorption on gold nanoparticle colloids of different properties and size

“…Poznato je da cijanske boje različitih struktura mogu formirati J-agregate u prisustvu molekula proteina, površinski aktivnih jedinjenja, polimera, metalnih jona i nanočestica [18][19][20][21][22][23][24][25][26]. Ovakvi agregati imaju usku apsorpcionu traku, pomerenu ka crvenoj oblasti i visoke apsorbancije i polarizabilnosti u odnosu na traku monomerne vrste [2], pa zbog svojih ultrabrzih i nelinearnih optičkih svojstava, nalaze primenu u optičkoj opremi u telekominukacionim mrežama [27,28]. Poznato je da se ovi sistemi koriste i da bi promenili elektrodni potencijal određenih materijala, indukujući elektronski transport i povećavajući osetljivost slojeva na svetlost He-Ne lasera [29].…”

“…U slučaju Au, prisustvo dodatnog "interband" člana vodi ka destruktivnoj interferenciji između ekscitonske i plazmonske polarizacije i ka većoj transparentnosti (kad svetlost prolazi bez difuzije i distorzije, slobodan prolaz elektromagnetne radijacije) na rezonanciji ekscitona. Pošto ovaj minimum nestaje kroz fotoekscitaciju, jedna od mogućih primena za takav sistem je u vidu optičke opreme za ultrabrzo optičko limitiranje [27,28].…”