Formation of the "J-aggregate-surfactant" complex for three cyanine dyes (L-21, LC-1 and PIC) in binary solutions containing cationic surfactant CPB at the concentration higher than the critical micelle concentration has been observed. The complex formation causes a significant increase of J-aggregate luminescence quantum yield and a decrease of radiative lifetime. The model of exciton self-trapping suppression in the "J-aggregatesurfactant" complex that causes changes of luminescence parameters has been proposed.
The diindolenine derivative of squaraine dye Sq-2Me has been used as an exciton energy trap (an energy acceptor) for amphi-PIC J-aggregates in a solution. Using the modified Stern-Volmer equation, parameters of the energy transfer have been obtained. It has been revealed that 50% of J-aggregate luminescence is quenched in a binary DMF/water solution at the ratio trap/amphi-PIC ) 1:80 that corresponds to the exciton migration over 20 delocalization segments within the J-aggregate.
It this letter, we report the study of free radicals and reactive oxygen species (ROS) generation in water solutions containing gadolinium orthovanadate GdVO4:Eu3+ nanoparticles (VNPs) and their complexes with methylene blue (MB) photosensitizer. The catalytic activity was studied under UV-Vis and X-ray irradiation by three methods (conjugated dienes test, OH· radical, and singlet oxygen detection). It has been shown that the VNPs–MB complexes reveal high efficiency of ROS generation under UV-Vis irradiation associated with both high efficiency of OH· radicals generation by VNPs and singlet oxygen generation by MB due to nonradiative excitation energy transfer from VNPs to MB molecules. Contrary to that under X-ray irradiation, the strong OH. radicals scavenging by VNPs has been observed.Electronic supplementary materialThe online version of this article (10.1186/s11671-018-2514-5) contains supplementary material, which is available to authorized users.
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