An ever growing demand for efficient energy conversion, for instance in luminescent lamps, flexible screens and solar cells, results in the current significant growth of research on functionalized nanomaterials for these applications. This paper reviews recent developments of a new class of optically active nanostructured materials based on glasses doped with luminescent Ag nanoclusters consisting of only a few Ag atoms, suitable for mercury-free white light generation and solar down-shifting. This new approach, based solely on Ag nanocluster doped glasses, is compared to other alternatives in the field of Ag and rare-earth ion co-doped materials.

Sensors are increasingly present in the everyday life in widespread technological applications, and engineering smart systems able to simultaneously detect different physical quantities represents a scientific challenge. Taking advantage of the molecular chemistry realm that offers the possibility to finely adjust physical properties, it is demonstrated herein that the luminescent single‐molecule magnet [Dy(acac)3(H2O)2]·H2O (acac = acetylacetonate) acts as a dual and synchronous thermometric/magnetic optical sensor in large ranges (10.0–180.0 K and up to ≈45 T) holding the promise to detect their variations in future devices.

The nonlinear absorption of Ag atomic clusters and nanoparticles dispersed in a transparent oxyfluoride glass host has been studied. The as-prepared glass, containing 0.15 at.% Ag, shows an absorption band in the UV/violet attributed to the presence of amorphous Ag atomic nanoclusters with an average size of 1.2 nm. Upon heat-treatment the Ag nanoclusters coalesce into larger nanoparticles that show a surface plasmon absorption band in the visible.Open aperture z-scan experiments using 480 nm nanosecond laser pulses demonstrated nonsaturated and saturated nonlinear absorption with large nonlinear absorption indices for the Ag nanoclusters and nanoparticles, respectively. These properties are promising, e.g., for applications in optical limiting and object's contrast enhancement.

The linear and nonlinear optical properties of metal nanoparticles are highly tunable by variation of parameters such as particle size, shape, composition, and environment. To fully exploit this tunability, however, quantitative information on nonlinear absorption cross sections is required, as well as a sufficient understanding of the physical mechanism underlying these nonlinearities. In this work, we present a detailed and systematic investigation of the wavelength-dependent nonlinear optical properties of Ag nanoparticles embedded in a glass host, in which the most important parameters determining the nonlinear behavior of the system are characterized. This allows a proper quantification of absorption cross sections and elucidation of the excitation mechanism. Based on small-angle X-ray scattering measurements average particle diameters of 3 and 17 nm are estimated for the studied samples. The nonlinear optical properties of the nanoparticle−glass composite are studied in an extended wavelength range with the open aperture z-scan technique. The experiments reveal a strong dependence of the nonlinear optical response on the excitation wavelength. Based on the wavelengthdependent response, excited-state absorption is determined as the excitation mechanism of the nanoparticles. Electromagnetic simulations demonstrate that the contributions from electric field enhancement and plasmonic coupling between the particles in the diluted glasses are limited, which implies that the very high two-photon absorption cross section at 460 nm ((6.9 ± 1.6) × 10 6 GM for the 3 nm particles and (19.5 ± 2.2) × 10 9 GM for the 17 nm particles) is an intrinsic property. In addition, irradiance-dependent measurements elucidate the role of saturation of the excited-state absorption process on the observed nonlinearities.

CASSCF/CASPT2/RASSI quantum chemistry methods have been applied for the first time to model/ compute kinetics of luminescence of Ag nanoclusters dispersed within the bulk of oxyfluoride glass. Namely the Ag 4 2+ tetramers have been investigated because they are argued to be dominant Ag nanoclusters in these glasses. The experimental nano-to micro-and millisecond kinetics all have been modeled, fit, and explained using these quantum chemistry methods. The configuration-coordinate energy level diagram for the Ag nanoclusters has also been calculated by the CASPT2 method, being in agreement with our previous computation by density functional theory.