Assembling Near-Infrared Dye on the Surface of Near-Infrared Silica-Coated Copper Sulphide Plasmonic Nanoparticles.

Functionalization of colloidal nanoparticles with organic dyes, which absorb photons in complementary spectral ranges, brings a synergistic effect for harvesting additional light energy. Here, we show functionalization of near-infrared (NIR) plasmonic nanoparticles (NPs) of bare and amino-group functionalized mesoporous silica-coated copper sulphide (CuS@MSS and CuS@MSS-NH) with specific tricarbocyanine NIR dye possessing sulfonate end groups. The role of specific surface chemistry in dye assembling on the surface of NPs is demonstrated, depending on the organic polar liquids or water used as a dispersant solvent.

Impact of the thermal properties of the environment on the hot-band absorption-assisted single-photon upconversion.

Single-photon hot-band absorption-assisted anti-Stokes photoluminescence (ASPL) is a non-equilibrium process which causes a local cooling effect and which therefore is accompanied by a reverse heat flux from the warmer environment. Here, we demonstrate that the thermal properties of the medium, , its thermal conductivity and specific heat capacity, play a significant role in driving the ASPL of an emitter placed in it. Exploiting seven different solvents and the near-infrared tricarbocyanine dye as a single-photon upconverter, we show an obvious correlation of activation energy and the quantum yield (QY) of ASPL with the solvent thermal conductivity and specific heat capacity, respectively.

"Awakening" of the S Emission of Tricarbocyanine Dyes Stimulated by Interaction with Carbon Quantum Dots.

Anti-Kasha emission (i.e., the emission from S ( > 1) excited levels) of infrared chromophores which possess intensive absorption and S emission in the near-infrared region, but which are spectrally silent in the visible, is a challenging task for relevant applications such as energy conversion, bioimaging, sensitization of solar cells, optical sensors, and so on.

Reversible Charge Transfer with Single-Walled Carbon Nanotubes Upon Harvesting the Low Energy Part of the Solar Spectrum.

Here, the ability of a novel near-infrared dye to noncovalently self-assemble onto the surface of single-walled carbon nanotubes (SWCNTs) driven by charge-transfer interactions is demonstrated. Steady-state, Raman, and transient absorption spectroscopies corroborate the electron donating character of the near-infrared dye when combined with SWCNTs, in the form of fluorescence quenching of the excited state of the dye, n-doping of SWCNTs, and reversible charge transfer, respectively. Formation of the one-electron oxidized dye as a result of interactions with SWCNTs is supported by spectroelectrochemical measurements.

Sensitization of upconverting nanoparticles with a NIR-emissive cyanine dye using a micellar encapsulation approach.

Photon upconversion nanomaterials have a wide range of applications, including biosensing and deep-tissue imaging. Their typically very weak and narrow absorption bands together with their size dependent luminescence efficiency can limit their application potential. This has been addressed by increasingly sophisticated core-shell particle architectures including the sensitization with organic dyes that strongly absorb in the near infrared (NIR).

Excimer Emission in J-Aggregates.

An excimer in J-aggregates has been often considered as a self-trapped exciton originating from the free exciton excited on the same aggregate and relaxed through interaction with vibronic modes. Here we show that other types of excimers due to intermolecular off-diagonal interactions can be observed in J-aggregates of thiamonomethinecyanine dyes. These excimers arise owing to free excitons too, but they possess a longer formation time of more than 100 ps, indicating migration of free excitons to the excimer formation site, where they interact with a guest species in the ground state.

Fluorescent J-aggregates of cyanine dyes: basic research and applications review.

J-aggregates are fascinating fluorescent nanomaterials formed by highly ordered assembly of organic dyes with the spectroscopic properties dramatically different from that of single or disorderly assembled dye molecules. They demonstrate very narrow red-shifted absorption and emission bands, strongly increased absorbance together with the decrease of radiative lifetime, highly polarized emission and other valuable features. The mechanisms of their electronic transitions are understood by formation of delocalized excitons already on the level of several coupled monomers.