Conversão de energia utilizando nano e meso estruturas de BaHfO

Abstract

The perovskite oxide, BaHfO (BHO), was synthesized by the Microwave assisted hidrothermal Method and was investigated its structural, morphologic and its optical property, in order to analyze the in uence of surface elements or interstitial elements in the energy conversion process. The kinetic model time 10 x 2 3 n , with n = 0; 1; 2; 3 e 4, was used in the synthesis, on the other hand rate were maintained, 140

C e 10 C/minutes, respectively. Structural analyzes were studied using of X-ray di raction and Raman spectroscopy, the morphology was analyzed by scanning electron microscopy images (SEM), the optical property was avaliable by photoluminescence spectroscopy (PL) and for analysis of the surface and interstitial elements it was used thermogravimetric analysis (TG). The studied BHO system has spherical character and rough surface, also presents speci c characteristics of crystallization process by Oriented Growth and Ostwald Ripening, which together give rise to reverse crystallization identi ed by SEM images. The XRD patterns and Raman spectra show that the system BHO has structural change of long and short range and through the TG curves observed the presence of water molecules adsorbed at surface and chlorine atoms intercalated in BHO structure, and also exhibit a structural relaxation at high temperatures. The energy conversion process has been identi ed by PL, where there was a strong in uence of surface elements and interstitial about the energy conversion process. Thus the luminescent emissions has became less intense as to relax the structure or elements are removed by heat treatment. Thus this work was able to establish a correlation between the energy conversion process and its origin for perovskites at room temperature.