Síntese pelo método Pechini e caracterização de pós e filmes de ZnO dopado com cobalto.

Abstract

Developing methods suitable for the production of ceramic powders ha bccn of great relevancc loday. sincc lhe important propertics in cerami c depend large ly on lhe unique charactcristics of the powder used. Thcse cbaracteristics are affectcd by lhe method used to gene rate the powder. For applicalions that require high perfom1ance and lügh technology. such as thc clectronics industry, where more sophisticated ceramic powders are desirable, the way to obtain the powder must ensure high purity, reproduciblc and controlled chcmical compo ition. atomic uniformity and sma ll particle size. Based in this context. we propose the synthesis and structural characterization of powders and films of pure ZnO and doped with coba lt (Co2

+) with concentration of 0.025 to 0. 1 moles synthcsized by Pechini mcthod for futurc application in as optical material . Characterizations b) X-ray diffraction. textura! analy is by 2 from the BET method, scanning electron microscop) analy is and thennogra\ imctry (TG) were performed. The compositions with values of 0.05; 0.075 and 0. 1 moles of cobah showed the presence of the second phase of cobalt oxide (Co203) and the desired phase of ZnO. According to the results. onl y the composition \\ ith concentration of 0.025 moles of cobalt presented a monophasic phase. o. it was cho en this last composition for the production of thi n films. The result of X-ray di ITraction for the ftlm doped with 0.025 moles of Co showed that this structure is a typical hexagonal wurtzite. The analysis of AFM showed that the conccntration of Co do not influence the microstructure of thin films. which shO\\Cd spherical grains. The tran mission spectrum showed a we ll defi ned gap close to 4.8 cV. Measurcs of diffuse re tlcctancc of thin films shov.'ed th.ree peaks of ernissions: a band of the absorption around 590 11111 . a band close to 51 O nrn, and another at 650 nrn. which are respon iblc for the green color of thin films. The thin filrns of ZnO doped with coball and synthesizcd by Pechini melhod. ha\'e application as attenuators in lhe visible and near infrared rcgions. Moreover. thcy can be used a V filters.