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Room Temperature Synthesis of Cu2O Nanospheres: Optical Properties and Thermal Behavior

  • Daniela Nunes (a1), Lídia Santos (a1), Paulo Duarte (a1), Ana Pimentel (a1), Joana V. Pinto (a1), Pedro Barquinha (a1), Patrícia A. Carvalho (a2), Elvira Fortunato (a1) and Rodrigo Martins (a1)...


The present work reports a simple and easy wet chemistry synthesis of cuprous oxide (Cu2O) nanospheres at room temperature without surfactants and using different precursors. Structural characterization was carried out by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy coupled with focused ion beam and energy-dispersive X-ray spectroscopy. The optical band gaps were determined from diffuse reflectance spectroscopy. The photoluminescence behavior of the as-synthesized nanospheres showed significant differences depending on the precursors used. The Cu2O nanospheres were constituted by aggregates of nanocrystals, in which an on/off emission behavior of each individual nanocrystal was identified during transmission electron microscopy observations. The thermal behavior of the Cu2O nanospheres was investigated with in situ X-ray diffraction and differential scanning calorimetry experiments. Remarkable structural differences were observed for the nanospheres annealed in air, which turned into hollow spherical structures surrounded by outsized nanocrystals.


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