水溶液下合成具有可調控粒徑大小的小顆氧化亞銅奈米粒子以及晶面光學性質探討

Synthesis of small Cu2O nanocubes and octahedra in aqueous solution with tunable sizes and their facet-dependent optical properties

柯韋宏(Wei-Hong Ke)

指導教授 ： 黃暄益

國立清華大學/理學院/化學系/碩士(2015年)

https://doi.org/10.6843/NTHU.2015.00083

摘要

本文利用兩種無添加界面活性劑的方法在10分鐘內合成出可大範圍調控粒徑的小顆八面體及正立方體氧化亞銅。其方法為在水相系統中混合硝酸銅(Cu(NO3)2)、聯胺(N2H4)、和不同體積的氫氧化鈉(NaOH)溶液，可得到頭對頭距離為52奈米變化至157奈米的八面體氧化亞銅。而正立方體氧化亞銅邊緣長度由9奈米變化至87奈米則可藉由水相於35 ºC下混合硫酸銅(CuSO4)，和不同體積的氫氧化鈉 (NaOH)，以及抗壞血酸(ascorbic acid)合成。這些粒徑大小皆可以被系統性的控制，這也表示超小氧化亞銅奈米粒子的形狀大小與控制在此獲得了突破。過去曾在金-氧化亞銅核殼雙層結構(Au‒Cu2O core‒shell nanocrystals)及鈀-氧化亞銅核殼雙層結構(Pd‒Cu2O core‒shell nanocrystals)的光譜中，觀察到具{100}晶面的正立方體有比具{111}晶面的八面體更紅位移的現象，本研究藉由比較一系列體積接近正立方體及八面體氧化亞銅的UV吸收光譜，發現正立方體相對於八面體的吸收峰可保持約15奈米的紅位移，故可證明氧化亞銅奈米粒子在光學上的晶面效應。

關鍵字

氧化亞銅 ； 奈米 ； 形狀控制 ； 尺寸控制 ； 半導體 ； 化學光譜

並列摘要

Here we report two surfactant-free methods for synthesis of small Cu2O octahedra and nanocubes with a large range of size tenability in just 10 min. Cu2O octahedra with corner-to-opposite corner distance varying from 52 nm to 157 nm have been obtained by simply mixing aqueous Cu(NO3)2 solution, N2H4 solution, and different volumes of NaOH solution. Cu2O nanocubes with edge lengths from 9 nm to 87 nm can be synthesized by mixing aqueous CuSO4 solution, different volumes of NaOH solution, and ascorbic acid solution at 35 ºC. The particle size can be controlled systematically. This represents the highest level of size and shape control for ultrasmall Cu2O nanocrystals which have been difficult to make. By comparing cubes and octahedra with similar sizes in terms of particle volume for their optical absorption spectra, nanocubes are consistently more red-shifted than octahedra by approximately 15 nm, proving convincingly that Cu2O nanocrystals possess facet-dependent properties, and that cubes bound by the {100} facets have a more red-shifted absorption band similar to observations made in Au‒Cu2O and Pd‒Cu2O nanocrystals.

參考文獻

(2)Chiu, C.-Y.; Huang, M. H. J. Mater. Chem. A 2013, 1, 8081−8092.

(4)Huang, W.-C.; Lyu, L.-M.; Yang, Y.-C.; Huang, M. H. J. Am. Chem. Soc. 2012, 134, 1261−1267.

(5)Ho, J.-Y.; Huang, M. H. J. Phys. Chem. C 2009, 113, 14159−14164.

(6)Kuo, C.-H.; Huang, M. H. J. Phys. Chem. C 2008, 112, 18355−18360.

(11)Lyu, L.-M.; Wang, W.-C.; Huang, M. H. Chem.‒Eur. J. 2010, 16, 14167−14174.