We studied luminescent properties of Pr3+ complex with pyrazole and 1, 10-phenanthroline ligand environment. It was demonstrated that the complex exhibits so-called “antenna” effect which involves ...the electronic excitation transfer from the ligands to the rare-earth ion. The observed complex structure of the luminescence spectrum specific to Pr3+ indicates that in the investigated compounds the luminescence originates from the rare-earth ion exclusively. The obtained data provided a means to identify the electronic transitions in the ion and to develop the corresponding energy diagram. Fluorescence lifetime imaging revealed uniform distribution of luminescence decay times for the Pr3+ complex crystalline phase. Consequently, the Pr3+ complex under study has one type of emission sites.
The report proposes a discussion of the effective combination of two current trends: the additive 3D printing method and the development of multicomponent photonic schemes, as well as the development ...of the foundations of additive scalable and flexible optical technology for creating interconnects and optical structures, which can solve problems such as the creation of interchip optical compounds, various optical and quantum-optical systems on a chip (resonators, modulators, photon detectors, single-photon radiation sources, etc.).
There are a few materials where single-photon emitters, which are vital elements of quantum communications, can be created and function at room temperature. One of these materials is hexagonal boron ...nitride. In this study, mechanically assembled homostructures made of two boron nitride sheets are investigated. At the interface between these sheets, microbubbles are formed by adsorbed residues of water molecules and carbon compounds. After high-temperature annealing of the samples, stable room-temperature emitters of single photons in the visible and near infrared bands are formed in the areas of these microbubbles. The observed phenomenon opens the way to the controlled creation of stable emitters using the assembly of homostructures.
Formation of nanoparticles of both ZnSe and CdS under ablation of corresponding bulk semiconductors in liquid environment (diethyleneglycol, ethanol, etc.) using radiation of a Cu vapor laser is ...reported. X-ray diffraction (XRD), resonance Raman scattering (RRS), and transmission electron microscopy (TEM) confirm that the nanoparticles are crystalline and have average size of ca 10–20 nm. RRS of nanoparticles are characterized by several peaks multiple to frequency of corresponding phonon (LO replicas).
We calculate scattering, absorption, and extinction spectra for triangular silver nanoprisms and plasmonic nanopatch antennas (NPAs). We demonstrate that for the nanopatch antennas involving ...nanoprisms with a lateral size of 40–120 nm absorption prevails over scattering. Plasmon resonance for the nanoprism in water and for the NPA is redshifted relative to that for the nanoprism in air. For a single NPA plasmon resonance is redshifted with increasing the nanoprism lateral dimensions, and blue-shifted with increasing its height. We provide a guideline to optimization of the NPA design with the NPAs involving 630 nm quantum dots taken as an illustrative example.
We studied luminescent properties of two Nd3+ complexes with two different ligands. The first one was 1,3-diketone bearing a pyrazole fragment and the second ligand was either 1,10-phenanthroline or ...EtOH. For the ligand environment composed of 1,3-diketone and 1,10-phenanthroline the position of the hybrid triplet level was as low as 18200 cm−1. The spectral features specific to Nd3+ emission observed in the photoluminescence spectra of the complexes under optical excitation provided the evidence for ion-centered luminescence. Radiative transitions were identified using the obtained spectroscopic data. Corresponding diagram of the energy levels of the complex with 1,10-phenanthroline ligand was developed. Possible energy transfer pathways were discussed.
•Nd3+ complexes with new 1,3-diketonate ligands were designed.•Nd3+-centered luminescence mechanism involving “antenna” effect is demonstrated.•Transition rates in Nd3+ were calculated in the framework of the Judd-Ofelt theory.
We performed spectroscopic investigations of four novel Sc(III) metal-organic complexes with β-diketonate ligands. It was demonstrated that bonding the ligands with an optically passive Sc(III) ion ...leads to sensitization of the luminescence of the complexes and affects their optical absorption spectra. Luminescence decays of the complexes exhibit non-exponential behaviour. From spatially-resolved decay measurements we evaluated the number of different sites responsible for the luminescence in the investigated complexes. Small variations of the ligand structure significantly affects the wavelength of emission maximum. This phenomenon may occur due to the difference in crystal packing of the complexes or formation of charge-transfer states.
•A new class of luminescent materials based on scandium β-diketonates was investigated.•Minor change in the ligand structure leads to prominent shift of the complex emission peak.•Bonding Sc (III) ion with β-diketonate ligands activates luminescence of the ligands.•Scandium (III) β-diketonates exhibited luminescence decay times of 1–8 ns.•Different origin of emission sites was discovered for studied Sc (III) β-diketonates.
The efficiency of electronic-excitation energy transfer from organic semiconductor TPD to CdSe/CdS/ZnS nanocrystals passivated with different organic ligands is investigated. It is shown that the ...rate of energy transfer from TPD to nanocrystals decreases with increasing thickness of the passivation coating. It is suggested that the Förster mechanism is responsible for the excitation transfer.
Abstract
We present a way for micro-lens and micro-lens array fabrication on the fiber facet by direct laser writing (DLW) method. The proposed setup for DLW printing on the fiber facet can protect ...objective lens and makes it possible to safely using a wide range of resists. Microlens fabricated on the single-mode optical fiber facet is demonstrated. Based on lens-on-fiber system we proposed concept of the micro-lenses on baseplate array printed on the multi-core fiber, where each lens is rigidly aligned with the core. One of the possible micro-lenses on the baseplate array is presented and its optical properties such as focal spot size and resolution are investigated. The possible application of the proposed micro-lens array is complex optical elements, such as micro-objectives with optimized optical design. Moreover, suggested freeform lens array can find application in high-accuracy wavefront sensing.
We investigated emissive properties of CdTe colloidal quantum wells (CQWs) in applied electric fields in the range of 0–90kV/cm. Photoluminescence spectra and time-resolved intensities of the ...excitonic peak were studied. The emission was centered at 2.47eV with a width of 40 meV. No visible broadening or redshifts were detected in the whole range of applied fields. We obtained the dependencies of integrated intensity and maximum intensity of interband luminescence on the magnitude of applied electric field with the decrease of these characteristics by 15–20% at 90kV/cm due to field-controlled charge carrier separation. Deceleration of the radiative decay rates with increasing electric field provides the evidence of field-controlled temporary exciton storage as two-fold increase of the number of photons registered in the 1–40ns time range is observed. This assertion is also confirmed by the growth of the luminescence integrated intensity in the electric fields in the range 30–60kV/cm. These findings are an important step toward understanding of the influence of electric fields on the operation of hybrid organic-inorganic LEDs with CQW-based emissive layers.
•Reversibility of action of electric field (EF) on colloidal quantum wells is found.•Final emission intensity exceeds the initial one due to long-lived charge carriers.•EF controls temporary exciton storage in CdTe quantum wells.•EF of 105V/cm doesn’t induce emission shifts or broadening in 2D nanocrystals.
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