Resposta termo-óptica de vidros com matrizes: 1 – PZABP nanoestruturado com nanocristais De ZnMnTe; 2 – BBPT dopado com íons Nd3+

Abstract

This research aims to study the thermo-optical properties of Phosphate glasses (PZABP) and also to synthesize and characterize, through spectroscopic techniques, a glassy matrix Borotelluride (BBPT). The study was divided into two groups. In the first, the characterization of diluted Zn1-xMnxTe magnetic semiconductor nanoparticles with host matrix (PZABP) was proposed. For this, Zn1-xMnxTe doped glasses were used, which became attractive due to their optical characteristics, energy quantization and quantum confinement. The thermo-optical properties were analyzed in the phosphate matrix with the nominal composition: 65P2O5 14ZnO 1Al2O3 10BaO 10PbO (% mol), which contains nanoparticles of Zn1-xMnxTe, with x (0,0 – 0,8) (% by weight ). The reagents were melted at 1300o C for 30 minutes, with thermal treatment for 10 h, under a temperature of 500°C for nucleation of the nanoparticles. Optical characterization was performed at room temperature using the following techniques: Optical absorption-UV-VIS, we note the absorption bands of Mn ions, and of ZnTe nanoparticles in the form of PQs and bulk. The structural units of the phosphate glass network formers are identified from the FT-IR and Raman spectra. Time correlated photon counting (TCSPC) spectra were performed at excitation wavelengths of 400 nm and 309 nm and emission 604 nm and 461 nm, respectively. According to the excitation, the sample showed variable chromaticity between blue, yellow and red. Time correlated photon count (TCSPC) spectra were performed at excitation wavelengths of 400 nm and 309 nm and emission 604 nm and 461 nm, respectively. According to the excitation, the sample showed variable chromaticity between blue, yellow and red. Thermal properties were obtained via thermal lens spectroscopy, which resulted in thermal diffusivity (D) and thermal conductivity (K) between (1,94 – 2,58) x 10-3 cm2 / sec and (3,996 – 6,914) x 10-3 W/cm K respectively and the rate of change of the optical path with temperature varied in the range of (0,914 – 3,56) x 10-6 K-1 . Non-linear Z-scan measurements, at 800 nm, showed a negative non-linear absorption index for the 20% ZnMnTe sample, indicative of the absorption of two photons. The 1% and 10% samples indicated saturated absorption signals, while for the 80% sample it was not possible to obtain a signal. It was concluded that the 20% sample is promising for non-linear devices with spin polarization. In the second group, the BBPT glass matrix was used (B2O3 + Bi2O3 + PbO + TeO2 + Nd2O3 (molar %), with variation in the amounts of B2O3 between 35 and 60 mol% and TeO2 changing from 0 to 25 mol%) doped with 0,5Nd3+. The reagents were melted (melting/cooling) at 1050°C for 1 hour and underwent heat treatment for 2 hours at a temperature of 350°C to improve the nucleation of the nanoparticles. Initially, the electronic transitions in the UV-Vis spectrum were observed, then; values of density and number of ions were shown. In the Raman spectrum, the IR absorption bands are associated with the vibrational modes B2O3 and TeO2 in the glass matrix. Additional information about the glassy nature of the samples was confirmed by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Thermal properties were obtained by means of thermal lens spectroscopy. In general, the glasses showed good optical transparency from the mid-infrared region to the blue region (450 nm). The samples with 25% of TeO2 and 35% of B2O3 were the ones that, in principle, presented the lowest phonon energies. Due to the higher presence of TeO2, it is assumed that these samples should have the highest non-linearity and that, therefore, this glass has potential for solid-state lasers and non-linear devices.