ZnO nanoparticles with controlled shapes and sizes prepared using a simple polyol synthesis

Polyol synthesized aluminum doped zinc oxide nanoparticles - influence of the hydration ratio on crystal growth, dopant incorporation and electrical properties

“…With increasing hydration ratio the particles change their form from spherical to rod-shaped particles. Lee et al [19] investigated the influence of the hydration ratio on the particle growth of polyol synthesized undoped ZnO particles and also observed a rod-shaped growth for ZnO particles with increasing hydration ratio. They developed a reaction mechanism for the water mediated growth and explain that the hydration ratio mediated particle-growth in ZnO is based on the fact that water acts both as reactant and as product of the hydrolysis and condensation reaction for the oxide formation and affects the kinetics of the nucleation and growth process, as well as Poul et al [20] generally describe.…”

“…Beneath the porosity, the shape and size of the nanoparticles can have a big impact on the coating's properties. By using bigger particles it is possible to minimize the amount of grain boundaries resulting in an improvement of the electrical properties [13,18,19], whereas particles bigger than 100 nm should not be used if highly transparent coatings are necessary as these big particles scatter the visible light and lower the transmittance of the coatings [11]. All in all, particle coatings with high transparency and good electrical properties can be achieved using particles of sufficiently small size and good conductivity which can be dispersed free of agglomerates.…”

“…To control the shape of the nanoparticles we add different amounts of water to the precursor solution as described by Lee et al [19] who obtained spherical and rod-shaped ZnO nanoparticles using this method. We investigate the influence of the hydration ratio and the dopant on the crystal-size and shape by X-ray powder diffraction (PXRD) analysis and scanning electron microscopy (SEM) and the electrical properties by resistance measurements of the bulk material.…”

Nanopartículas de óxido de zinco sintetizadas pelo método poliol: caracterização e avaliação da atividade antibacteriana

“…De acordo com [15], a água pode agir não só como reagente na reação de hidrólise (equação 1), mas também como produto na reação de condensação (equação 2b). Com isso, a razão de hidratação pode afetar tanto a taxa de hidrólise quanto a taxa de condensação do precursor do Zn na solução, através da qual partículas de ZnO podem ser nucleadas para, posteriormente, crescerem.…”

“…Na Figura 2 são apresentados os difratogramas de raio-X para as amostras sintetizadas com e sem poli(vinil pirrolidona). Todos os picos de difração de Bragg, devidamente especificados nos difratogramas, são típicos de cristais de óxido de zinco com estrutura hexagonal (wurtzita), conforme reportado na literatura [15] e [17]. A não existência de picos extra demonstram que os nanocristais de óxido de zinco sintetizados possuem elevado grau de pureza, e a cristalidade do material parece não ter sido afetada pela adição do agente estabilizante poli(vinil pirrolidona) durante o processo de síntese.…”