Search results for "luminescence."
showing 10 items of 1568 documents
Ultrafast and long-time excited state kinetics of an NIR-emissive vanadium(iii) complex I: synthesis, spectroscopy and static quantum chemistry.
2021
In spite of intense, recent research efforts, luminescent transition metal complexes with Earth-abundant metals are still very rare owing to the small ligand field splitting of 3d transition metal complexes and the resulting non-emissive low-energy metal-centered states. Low-energy excited states decay efficiently non-radiatively, so that near-infrared emissive transition metal complexes with 3d transition metals are even more challenging. We report that the heteroleptic pseudo-octahedral d2-vanadium(iii) complex VCl3(ddpd) (ddpd = N,N′-dimethyl-N,N′-dipyridine-2-yl-pyridine-2,6-diamine) shows near-infrared singlet → triplet spin–flip phosphorescence maxima at 1102, 1219 and 1256 nm with a …
Multi-scale dynamics simulations of molecular polaritons: The effect of multiple cavity modes on polariton relaxation
2021
It is included two versions of this item: the Accepted Version which is already Open Access and the Published Version which is under an embargo period till 2022-03-09.
Seasonal variation of air kerma rate in Sicily.
2007
Thermoluminescence dosimetry has been used to measure air kerma in 29 sites in Sicily. Four three month measurement campaigns have been carried out in order to assess seasonal variations. Average annual values between 20 and 90 nGy h(-1), after cosmic background subtraction, are reported. Average annual values are strongly dependent on site lithology, and we find that winter data are generally the highest, while spring and autumn rates are generally the lowest with very similar trends in any site. Summer values generally lay in between. Largest seasonal variations are found in sites along the southern coast of the island, probably because of stronger action of winds affecting radon, along w…
Tunneling luminescence in long lasting afterglow of SrAl 2 O 4 :Eu,Dy
2017
The publication is prepared with the financial support of National Research Programme IMIS2.
Luminescence and structural properties of defects in ion implanted ZnO
2006
ZnO substrates and films were intentionally implanted with rare earth and transition metal ions. The influence of the implantation and subsequent air thermal annealing treatments on the structural and optical properties of ZnO samples were studied by using Rutherford backscattering spectrometry and low temperature photoluminescence techniques. Intraionic Tm-related emission was observed for bulk and ZnO films. Similarly, Eu and Tb-doped ZnO films follow the same trend observed in bulk samples. No intraionic related emission was observed for Eu-doped samples even being the ion in Zn sites and for the Tb-doped samples ion segregation was observed for thermal annealing temperatures above 800 °…
Génération et détection d'électrons chauds dans des dispositifs plasmoniques
2021
Hot carrier-based devices are quite promissing for ultrafast photodetection and toset off enhanced physicochemical reactions. Controlling their generation at the nanoscale within plasmonic devices is a key for the future development of hybrid hot carriers technologies. Indeed, Surface PlasmonPolaritons (SPPs) can be exploited to confine light and enhance the number of excited hot carriers. We aim at studying the excitation and dynamics of hot carriers, enhanced by plasmonics, with two different approaches.In a first approach, we aim at controlling the delocalized generation of hot carriers by a propagative SPP. A plasmonic waveguide with a grating coupler is employed. Hot electrons are indi…
Chemi- and Bioluminescence of Cyclic Peroxides
2018
Bioluminescence is a phenomenon that has fascinated mankind for centuries. Today the phenomenon and its sibling, chemiluminescence, have impacted society with a number of useful applications in fields like analytical chemistry and medicine, just to mention two. In this review, a molecular-orbital perspective is adopted to explain the chemistry behind chemiexcitation in both chemi- and bioluminescence. First, the uncatalyzed thermal dissociation of 1,2-dioxetane is presented and analyzed to explain, for example, the preference for triplet excited product states and increased yield with larger nonreactive substituents. The catalyzed fragmentation reaction and related details are then exemplif…
Probing the self-assembly and stability of oligohistidine based rod-like micelles by aggregation induced luminescence.
2016
OA hybrid The synthesis and self-assembly of a new C2-symmetric oligohistidine amphiphile equipped with an aggregation induced emission luminophore is reported. We observe the formation of highly stable and ordered rod-like micelles in phosphate buffered saline, with a critical aggregation concentration below 200 nM. Aggregation induced emission of the luminophore confirms the high stability of the anisotropic assemblies in serum.
Luminescent supramolecular heterometallic macrocycles and their encapsulation on cholate gels
2018
The metal complex formed by coordination of Zn(II) to 1,7-bis(4-methylpyridine)-4-(2- naphthylmethyl)-1,4,7-triazaheptane (ZnL2+) was reacted in aqueous solution with [Pd(NO3)2(en)] and [Pt(NO3)2(en)] salts to form the self-assembled heterometallic macrocycles [Zn2L2Pd2(en)2]8+ and [Zn2L2Pt2(en)2]8+, respectively. Pd(II) and Pt(II)- coordination modulates the original emission of ZnL2+ arising from the presence of the naphthalene chromophore and the formation of the macrocycles can be monitored due to the PET process occurring with coordination of Pd(II) and Pt(II) to the pyridine units of ZnL2+. Additionally, several studies reveal that these heteromacrocycles can be encapsulated in Zn(II)…
Gp91phox-containing NAD(P)H oxidase increases superoxide formation by doxorubicin and NADPH
2006
Doxorubicin is a highly effective antineoplastic drug associated with a dose-dependent cardiotoxicity that may result in irreversible cardiomyopathy and heart failure. Gene variants of the superoxide-generating enzyme NAD(P)H oxidase have recently been associated with this phenotype. We investigated the mechanism of this association using lucigenin-enhanced chemiluminescence, spectrophotometry, electrochemical sensor, and electron paramagnetic resonance spectroscopy. Superoxide production was measured in female wild-type and NAD(P)H oxidase-deficient (gp91phox knockout) mice. The magnitude of the increase in superoxide production on the addition of doxorubicin was much higher in hearts of w…