Dimitrije Mara

Lanthanide‐based optical emitters are emerging as promising materials for quantum applications because of the long optical coherent lifetimes associated with their narrow emission lines. In this work, we investigate a series of lanthanide molecular complexes with a highly rigid tetrapodal benzimidazolic ligand ( L ) as potential highly coherent quantum light sources suitable for on‐chip integration. The LnL complexes show sensitized Ln‐centered emission in the visible and near‐infrared spectral ranges with a well‐resolved fine structure of the J sublevels. Remarkably, the EuL complex exhibits a single line related to the purely electric dipole ⁵ D ₀ → ⁷ F ₀ transition, of particular interest in quantum photonics. Notably, this formally forbidden line likely originates from an LMCT state, rather than from low symmetry or strong crystal‐field effects. This mechanism enables the appearance of the band while maintaining a limited electric inhomogeneity of the ligand system, as supported by Judd–Ofelt analysis. These features contribute to the significant reduction of the room‐temperature inhomogeneous linewidth (∼500 GHz) compared to typical zero‐phonon lines of polyaromatic molecules in polymers. Importantly, these favorable properties persist in doped silica‐based SiCO and PMMA films. Additionally, the doped SiCO film provides high excitation selectivity, minimal host autofluorescence, and broad color tunability.

Plastic has transitioned rapidly from a revolutionary material to a global environmental concern, primarily due to mismanagement. Synthetic polymers have quickly gained widespread use due to their versatility, durability, and affordability. However, the properties making plastic indispensable contribute to its permanence in the environment, where it breaks down into microplastics—tiny particles that are typically classified in the size range from 0.1 μm to 5 mm. These particles can now be found in all ecosystems, including the oceans, soil, atmosphere, and within living organisms, raising global concerns about their long-term environmental and health impacts. This review critically examines the current status and potential for identifying, analyzing, and mitigating microplastic pollution. In this paper, we particularly focus on the destructive and non-destructive analytical methods used for microplastic identification and characterization, examining their technical capabilities and limitations, the challenges in maintaining sample integrity, and the reliability of their quantification methods. In addition, the review addresses microplastic removal strategies, from laboratory procedures to real-world applications, examining barriers to implementation and the limited availability of existing solutions. Finally, the review highlights the urgent need for standardized protocols, regulatory frameworks, and interdisciplinary collaboration to address the multifaceted nature of microplastic pollution.

Owing to their unique luminescent properties and photosensitizing capability, cyanoruthenium(II) complexes with diimine lig-ands are the subject of intense research striving for routes for tuning their electronic properties and improving their emission quantum yield. In this work, we describe the first example of a heterometallic d-f cyanide-bridged Ru(II)-Er(III) assembly ob-tained by the direct reaction of trivalent erbium salt with the neutral [Ru(bipy)2(CN)2] metalloligand. This strategy allows for accommodating inorganic negatively charged anions, such as nitrate and oxalate, in the coordination sphere of the lanthanide ion. As a result, a dimeric tetranuclear discrete molecular architecture is obtained, where the two constituting monomeric Ru(II)-CN-Er(III) units are bridged by an oxalate anion coordinating two Er(III) ions in a bis-bidentate fashion. Strikingly, this heter-ometallic compound shows intense dual emission in the visible and near-infrared spectral ranges under single-wavelength exci-tation both in solution and in the crystalline state. The effect of Er(III) coordination through a cyanide bridge is thoroughly dis-cussed, also with the support of DFT calculations, to highlight the factors that induce the observed spectral hypsochromism and, more importantly, the remarkable tenfold-increased emission quantum yield of the [Ru(bipy)2(CN)2] moiety in the visible range. We show that the described coordination mode induces an energy raise of the emissive 3MLCT state and even a more pronounced lifting of the non-emissive Ru(II) 3MC states, suppressing thermal deactivation channels. Furthermore, thanks to the reduced number of water molecules and quenching groups surrounding the lanthanide ion in the molecular architecture, rel-atively intense erbium emission at 1.5 μm telecom wavelength is detected through the sensitization from the Ru(II) metallolig-and. We suggest that this compound can find applications as efficient solid-state dual emitter and luminescent chemical sensor.

The self-assembly reaction of the neutral dicyano-bis(1,10-phenanthroline) iron(II) complex with lanthanide ions (Ln = Eu(III), Gd(III), Er(III)) provided two different classes of heterometallic cyano-bridged 3d-4f architectures depending on the nature of the counteranion, irrespective of the size of the 4f metal ion. Tetranuclear oligomers with a squared Fe₂Ln₂ core were isolated when using nitrate salts, whereas unusual 1D polymeric chains were obtained when resorting to triflate salts under the same synthetic conditions. It is shown that the different structural motifs have a remarkable impact on the thermal stability and the optical properties of the compounds, which display a notable optical ipsochromism of the parent Fe(II) complex upon coordination with the Ln ion. This effect is significantly more pronounced in the polymeric chain than in the Fe₂Ln₂ oligomer both in solution and in the solid state. Structural evidence suggests that this behavior is likely related to the geometry of the CN-Ln bridge. On the other hand, more extended π-stacking interactions in the oligomer give rise to a broad charge-transfer absorption (600–1500 nm), making this compound promising as NIR absorber. Density Functional Theory calculations and electrochemical studies demonstrate that the observed negative chromism originates from the stabilization of a mixed metal/cyanide character HOMO with respect to a phenanthroline-centered LUMO.

The material?s size and shape influence its physical, chemical and mechanical properties. This study describes an investigation of natural photonic structure of the butterfly?s wing, mainly composed of chitin. The effect of corrugations at the nanoscale on material?s optical response is unambiguously revealed in the presented thermal measurements. Furthermore, the presented study shows the possibility of exploiting holography to monitor dynamics in situ.

Lanthanide hydrogen-bonded organic frameworks (LnHOFs) are recently emerging as a novel versatile class of multicomponent luminescent materials with promising potential applications in optics and photonics. Trivalent europium (Eu³⁺) incorporated polymeric hydrogen-bonded triazine frameworks (PHTF:Eu) have been successfully obtained via a facile and low-cost thermal pyrolysis route. The PHTF:Eu material shows a porous frame structure principally composed of isocyanuric acid and ammelide as a minor constituent. Intense red luminescence with high colour-purity from Eu³⁺ is obtained by exciting over a broad absorption band peaked at 300 nm either at room or low temperature. The triazine-based host works as excellent optical antenna towards Eu³⁺, yielding ~42% sensitization efficiency (η_sens) and an intrinsic quantum yield of Eu³⁺ emission (Φ_Eu) as high as ~46%. Temperature-dependent emission studies show that PHTF:Eu displays relatively high optical stability at elevated temperatures in comparison to traditional inorganic phosphors. The retrieved activation energy of 89 meV indicates that thermal quenching mechanisms are attributed to the intrinsic energy level structure of the metal-triazine assembly, possibly via a thermally activated back transfer to ligand triplet or CT states. Finally, by using an innovative approach based on excitation spectra, we demonstrate that PHTF:Eu can work as a universal primary self-referencing thermometer based on a single-emitting center with excellent relative sensitivity in the cryogenic temperature range.