Optical spectroscopy of Nd3+ ions in a nanostructured glass matrix

This paper presents the optical characterization of Nd3+ ions in nanostructured SiO2-Na2CO3-Al2O3-B2O3 (SNAB) CdS glass, synthesized by fusion. Radiative properties of the glass were determined by absorption, luminescence spectroscopy and lifetime measurements. Nd3+ emission enhancement and quenching were investigated in the presence of CdS nanocrystals. Nd3+-emission quenching was attributed to upconversion mechanisms and nonradiative processes such as multiphonon decay and energy transfer, while the Nd3+-emission enhancement was due to energy transfer from the CdS nanocrystals. Changes in the chemical environment around CdS nanocrystals were also confirmed by Judd-Ofelt calculations.CNPqFAPEMIGCAPE

Thermal diffusivity of a SNAB glass system doped with CdS nanocrystals and Nd3+

This work reports on the thermal diffusivity of the SiO2-Na2CO3-B2O3-Al2O3 (SNAB) glass system doped with semiconductor nanocrystals of CdS and Nd3+ ions. Thermal diffusivity (D) was obtained by the Thermal Lens technique. It is shown that D decreases up to 30% when SNAB is doped with CdS nanocrystals. The effect is discussed in terms of heat transport by phonons as well as interface and surface scattering.CAPESFAPEMIGCNP

Influence of crystal field potential on the spectroscopic parameters of\ud SiO2.B2O3.PbO glass doped with Nd2O3

This paper presents the optical characteristics of Nd3+ silicate glass (SiO2-B2O3-PbO), synthesized by the fusion method. Two sets of samples were prepared: glass and corresponding glass ceramics. Optical absorption, luminescence, Raman spectroscopy and atomic force microscopy (AFM) measurements were performed in order to determine the structural properties of the systems and the radiative characteristics of Nd3+ ions. Near infrared luminescence exhibited typical Nd3+ bands. Raman and AFM measurements indicated nanocrystal growth with thermal treatment of the glass ceramics. Judd-Ofelt calculations also confirmed that heat treatment induced structural rearrangement of the samples that was dependent on Nd2O3 concentration. This resulted in changes in the optical and physical properties of the samples, including stimulated emission cross section and rigidity.CNPqFAPEMIGCAPE

'Eu POT.3+' photoluminescence enhancement due to thermal energy transfer in 'Eu IND.2''O IND.3'-doped Si'O IND.2'-'B IND.2''O IND.3'-Pb'O IND.2' glasses system

In this work, Eu3+-doped lead borosilicate glasses (SiO2-B2O3-PbO2) synthesized by fusion method had their optical properties investigated as a function of temperature. Atomic Force Microscopy images obtained for a glass matrix annealed at 350 and 500 °C show a precipitated crystalline phase with sizes 11 and 21 nm, respectively. Besides, as the temperature increases from 350 to 300 K a strong Eu3+ photoluminescence (PL) enhancement takes place. This anomalous feature is attributed to the thermally activated carrier transfer process from nanocrystals and charged intrinsic defects states to Eu3+ energy levels. In addition, the PL peaks in this temperature range were assigned to the Eu3+ transitions 5D0→7F2, at 612 nm, 5D0→7F1, at 595 nm, and 5D0→7F0, at 585 nm. It was also observed that the 5D0→7F3 and 5D0→7F4 PL bands at 655 and 700 nm, respectively, show a continuous decrease in intensity as the temperature increases.CAPESMCT/CNPqFAPEMI

1.3 μm emitting SrF2:Nd3+ nanoparticles for high contrast in vivo imaging in the second biological window

Novel approaches for high contrast, deep tissue, in vivo fluorescence biomedical imaging are based on infrared-emitting nanoparticles working in the so-called second biological window (1,000–1,400 nm). This allows for the acquisition of high resolution, deep tissue images due to the partial transparency of tissues in this particular spectral range. In addition, the optical excitation with low energy (infrared) photons also leads to a drastic reduction in the contribution of autofluorescence to the in vivo image. Nevertheless, as is demonstrated here, working solely in this biological window does not ensure a complete removal of autofluorescence as the specimen’s diet shows a remarkable infrared fluorescence that extends up to 1,100 nm. In this work, we show how the 1,340 nm emission band of Nd3+ ions embedded in SrF2 nanoparticles can be used to produce autofluorescence free, high contrast in vivo fluorescence images. It is also demonstrated that the complete removal of the food-related infrared autofluorescence is imperative for the development of reliable biodistribution studie