Exploration of the Temperature Sensing Ability of La2MgTiO6:Er3+ Double Perovskites Using Thermally Coupled and Uncoupled Energy Levels

This work aimed to explore the temperature-sensing performance of La2MgTiO6:Er3+ double perovskites based on thermally coupled and uncoupled energy levels. Furthermore, the crystal structure, chemical composition, and morphology of the samples were investigated by powder X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy, respectively. The most intense luminescence was observed for the sample doped with 5% Er3+. The temperature-dependent emission spectra of La2MgTiO6:5% Er3+ were investigated in the wide range of 77–398 K. The highest sensitivity of the sample was equal to 2.98%/K corresponding to the thermally coupled energy level 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 as compared to 1.9%/K, obtained for the uncoupled energy level 2H11/2 → 4I15/2 and 2H9/2 → 4I15/2. Furthermore, the 300 K luminescent decay profiles were analyzed using the Inokuti–Hirayama model. The energy transfer among Er3+ ions was mainly regulated by the dipole–dipole mechanism. The critical transfer distance R0, critical concentration C0, energy transfer parameter Cda, and energy transfer probability Wda were 9.81 Å, 2.53×1020 ions·cm−3, 5.38×10−39 cm6·s−1, and 6020 s−1, respectively.

A Single Crystal Hybrid Ligand Framework of Copper(II) with Stable Intrinsic Blue-Light Luminescence in Aqueous Solution

Single-crystal solid–liquid dual-phase hybrid organic–inorganic ligand frameworks with reversible sensing response facilitated by external stimuli have received significant attention in recent years. This report presents a significant leap in designing electronic structures that display reversible dual-phase photoluminescence properties from single-crystal hybrid ligand frameworks. Three-dimensional Cu(C3N2H4)4Cl2 complex frameworks were formed through the intermolecular hydrogen bonding and π⋯π stacking supramolecular interactions. The absorption band peaks at 627 nm were assigned to d–d transition showing 10Dq = 15,949 cm−1 and crystal field stabilization energy (CFSE) = 0.6 × 10Dq = 114.4 kJmol−1, while the ligand-to-metal charge transfer (LMCT) of complexes was displayed at 292 nm. The intense luminescence band results from LMCT present at 397 nm. Considering its structure, air stability, framework forming and stable luminescence in aqueous solution, the Cu(C3N2H4)4Cl2 complex shows potential for luminescence Cu-based sensors using emission intensity to detect heavy metal ion species.

Assembly of Two New Coordination Polymers: Luminescent Properties and Anti-inflammatory Activity on Postoperative Infectious Endophthalmitis

The solvothermal reactions via the self-assemble approach produced two new metal-organic compounds, i.e, [Zn(4-cptpy)(HCOO)(H2O)]n·n(DMF) (1) and [Cd3(btc)2(4-cptpyH)(DMF)(H2O)3]n (2) (DMF is N,N’-dimethylformamide, H3btc is benzene-1,3,5-tricarboxylic acid, and 4-Hcptpy is 4-[2,6-bis(pyridine-4-yl)pyridine-4-yl]benzoic acid). Furthermore, the compounds’ luminescent performances have also been studied. As a result, compounds 1-2 show intense luminescence at room temperature. The evaluation of their application values against postoperative infectious endophthalmitis (PIE) was implemented and their specific mechanism was investigated. First of all, the real time reverse transcription-polymerase chain reaction (RT-PCR) was performed and the nuclear factor kappa-B (NF-κb) signaling pathway activation levels were measured. In addition to this, the inflammatory cytokines content released after the cataract surgery was determined through exploiting the enzyme linked immunosorbent assay (ELISA) detection kit.

Thermal, Spectroscopy and Luminescent Characterization of Hybrid PMMA/Lanthanide Complex Materials

Novel hybrid materials based on the poly(methyl methacrylate) (PMMA) matrix and lanthanide(III) carboxylates Eu:2,6-DClB and Tb:2,6-DClB were synthesized and carefully analyzed in the context of their potential application in optically active polymer-based optical fibers. To determine the usefulness of the obtained materials, a careful thermal, mass spectroscopy, and optical characterization was performed, focusing on the features critical for the technology of optical fiber processing. In addition, the luminescent features of both lanthanide complexes and the resulting hybrid composites were carefully investigated to identify the processes responsible for light emission and to analyze the influence of the PMMA host on light emission intensity and spectral characteristics. The obtained results showed that both lanthanide carboxylate complexes exhibited intense luminescence in the red and green spectral range, typical of europium and terbium dopants, and that those features were well preserved after introducing them into the PMMA polymer. Thermal analysis also proved that introducing the luminescent additives did not significantly affect the thermal properties of both hybrid materials, thus enabling further processing into the form of optical fibers.

New Heterometallic Compound as Luminescent Sensor for Detection of CS2 and Treatment Effect on Childhood Diabetes

The hydrothermal reaction of Cd(NO3)2·4H2O, KNO3 with the dicarboxylate ligand of 2-aminoterephthalic acid (H2L) yields a new heterometallic coordination polymer with the formula of [CdK2(L)2(H2O)4]n (1). Compound 1 emits intense luminescence at ambient temperature and shows high selectivity and sensitivity for the detection of CS2. Serial biological experiments were conducted to evaluate the activity of the new compound on children diabetes. First of all, after the compound treatment, the blood glucose meter was used to measure the levels of body's blood sugar. In addition to this, the relative expression levels of the insulin receptor on the liver cells were determined with real time RT-PCR.

Effect of metal concentration on growth and luminescence of luminous bacteria strains isolated from golfo de Nicoya, Costa Rica

Luminescence in bacteria is catalyzed by luciferase. When these microorganisms are exposed to toxic substances, the bioluminescent enzyme system can be inhibited. The objective of this study was to analyze the potential that these microorganisms offer as native bioindicators of coastal marine pollution. The dynamics of luminescence intensity by visual classification and the effect of metal concentration on the growth and luminescence of 25 strains of luminescent bacteria, isolated during 2016 from seawater samples from the gulf of Nicoya, Costa Rica, was evaluated by the disk diffusion method. The sensitivity of each strain to different concentrations (0.1, 0.5 and 1 mg mL-1) of Cd, Cu, Cr, Pb and Zn was determined by its bioluminescent phenotype. In susceptible strains, a range of metal concentrations less than the growth inhibitory concentration affected the expression of luminescence. Strains with intense luminescence and defined zones of luminescence inhibition were considered to have greater potential as native bioindicators for monitoring environmental toxicity. More studies are required to determine the minimum concentrations that inhibit growth and luminescence with respect to the tested metals and other potentially toxic substances for the coastal marine ecosystems of Costa Rica.

Mesomorphic Behavior of Symmetric Azomethine Dimers Containing Different Chromophore Groups

A series of new azomethine dimers was synthesized by the condensation reaction of flexible bis-benzaldehydes with four aromatic amines containing phenyl, naphthyl, anthracene and pyrene groups. Their right structure was confirmed by FTIR and 1H-NMR spectroscopy and their thermal properties were investigated by thermogravimetric analysis, differential scanning calorimetry and polarized light optical microscopy. A view on their photophysical behavior was gained by UV-vis and photoluminescence spectroscopy. The dimers containing pyrene and anthracene presented liquid crystalline behavior, while the other dimers were crystalline compounds. Two dimers containing pyrene moieties formed mesomorphic glasses and had intense luminescence, promising properties for applications in building optoelectronic devices.

Extended ligand conjugation and dinuclearity as a route to efficient platinum-based near-infrared (NIR) triplet emitters and solution-processed NIR-OLEDs

A complex in which two Pt(ii) ions are cyclometallated to bis-dithienylpyrimidine displays intense luminescence in the NIR region, both in solution and in an OLED.

Integrating molecular rigidity and chirality into thermally activated delayed fluorescence emitters for highly efficient sky-blue and orange circularly polarized electroluminescence

Two pairs of D*–A type blue and orange CP-TADF emitters based on a rigid point chiral donor reveal high molecular rigidity, excellent PLQYs, and intense luminescence dissymmetry factors, which jointly enable highly efficient CP-OLEDs.