Syntheses and characterizations of alloyed Co _x Ni_1−x O nanocrystals

Abstract

Alloying is an effective way to manipulate the composition and physico-chemical properties of functional materials. We demonstrated the syntheses of alloyed Co _x Ni_1−x O nanocrystals using a nonaqueous approach, with x continuously tuned from 0 to 1 by varying the molar ratios of the cobalt precursor in the reagents. The morphological, structural, and compositional properties of the alloyed Co _x Ni_1−x O nanocrystals were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and energy dispersive X-ray spectroscopy (EDS). The results showed that the cobalt and nickel atoms were homogeneously distributed in the alloyed nanocrystals. The as-prepared Co _x Ni_1−x O nanocrystals can be applied as the hole-transporting layers in polymer light emitting diodes (PLEDs). Our study provides a good example for the syntheses of alloyed oxide nanocrystals with continuously tunable composition.

中文概要

目 的

合成成分连续可调的Co _x Ni_1−x O 合金纳米晶, 揭 示Co _x Ni_1−x O 合金纳米晶的形貌和晶体结构随纳 米晶中钴离子含量的变化规律以及考察金属离 子在合金纳米晶的分布情况。

创新点

1. 利用金属羧酸盐在有机体系中的醇解反应制备 Co _x Ni_1−x O 合金纳米晶, 其反应温度仅为270 °C, 显著低于文献报道中所使用的温度; 2. 成功实现 Co _x Ni_1−x O 纳米晶成分的调节, 发现纳米晶形貌随 成分的变化规律; 3. 揭示了金属离子在合金纳米 晶中的均匀分布。

方 法

1. 在硬脂酸锂的“配体保护”作用下, 利用金属 羧酸盐的醇解反应制备Co _x Ni_1−x O 合金纳米晶; 2. 利用透射电子显微镜、X 射线衍射、原子发射 光谱和X 射线光电子等手段研究Co _x Ni_1−x O 合金 纳米晶的形貌、晶体结构、成分和金属离子价态 等信息。

结 论

1. 成功地制备出高质量的Co _x Ni_1−x O (x∈[0, 1])合 金纳米晶; 2. 发现Co _x Ni_1−x O 合金纳米晶的形貌 和晶体结构随纳米晶中钴离子浓度的提高呈现 出由NiO 特征过渡到CoO 特征的趋势; 3. 对单 颗Co _x Ni_1−x O 合金纳米晶的元素扫描揭示了金属 离子在纳米晶中的均匀分布。