铜纳米线的合成、优化及其透明电极的应用

doi:10.15541/jim20180243

摘要/Abstract

摘要：

随着光伏产业、平板显示技术的发展, 市场对于透明导电材料的需求量迅速增加。传统的透明导电材料氧化铟锡(ITO)面临着资源不足、脆性大的问题, 无法满足市场需求。铜纳米线透明电极导电性好、成本低、柔性好, 是一种有潜力的新一代透明导电材料。近年来, 铜纳米线的合成及其在透明导电领域的应用引起了研究人员的关注, 并取得显著的进展。本文从铜纳米线的合成方法、合成机理, 铜纳米线透明电极的制备方法及后处理手段, 铜纳米线透明电极在光伏器件、电加热元件、柔性可穿戴器件中的应用等方面的研究进展进行了阐述。并对铜纳米线研究及应用前景进行了展望。

关键词: 铜纳米线, 透明电极, 可控合成, 后处理, 光伏器件, 电加热元件, 柔性可穿戴, 综述

Abstract:

As the continuous development of the photovoltaic industry and the flat panel display devices, the demand for transparent electrodes is increasing rapidly. The most commonly used transparent conductive material, ITO, was criticized for its brittleness, which limited its application in the up-and-coming market. Cu nanowire transparent electrodes acts as promising candidate for the new generation of transparent electrodes due to their superior conductivity, low cost, easy accessibility and high flexibility. The synthesis of Cu nanowires and their application in transparent electrodes has drawn lots of attention. Progresses have been made in recent years. A comprehensive elaboration of the controllable synthesis of Cu nanowires through liquid synthesis methods and the mechanism behind them, the fabrication and post-treatment methods of Cu nanowire electrodes, the application of Cu nanowire electrodes in photovoltaic devices, transparent heaters and flexible devices are given. The trends of Cu nanowire electrodes is proposed.

Key words: Cu nanowires, transparent electrodes, controllable synthesis, post-treatment, photovoltaic devices, heaters, flexible and wearable devices, review

中图分类号:

TQ174

王晓, 王冉冉, 施良晶, 孙静. 铜纳米线的合成、优化及其透明电极的应用[J]. 无机材料学报, 2019, 34(1): 49-59.

WANG Xiao, WANG Ran-Ran, SHI Liang-Jing, SUN Jing. Synthesis, Optimization of Cu Nanowires and Application of Its Transparent Electrodes[J]. Journal of Inorganic Materials, 2019, 34(1): 49-59.

图/表 8

图1 液晶结构介质中铜纳米线形成机制示意图[14]

Fig. 1 Formation of Cu nanowires directed by liquid-crystalline structure of the medium[14]

表1 常见铜纳米线合成方法

Table 1 Summary of representitive synthetic methods of Cu nanowires

Solvent	Reducing agent	Capping agent	Cu precursor	Average diameter/nm	Average length	Ref.
DI water	H₃PO₃	Sodium dodecyl benzene sulfonate (SDBS)	CuSO₄·5H₂O,	~85	Tens of micrometers	[17]
DI water	Hydrazine hydrate	Ethylenediamine	Cu(NO₃)₂	35-70	20-80 μm	[11-13, 18]
DI water	Ascorbic Acid	PVP	Cu(NO₃)₂	~50	>10 μm	[19]
DI water	Glucose	HDA	CuCl₂·2H₂O	24±4	Tens to hundreds micrometers	[20]
DI water	Glucose	Oleic acid, Oleylamine	CuCl₂	~45	60-90 μm	[9]
1-hexadecylamine (HDA)	1-Hexadecylamine (HDA)	Hexadecyl trimethyl ammonium bromide (CTAB)	Cu(acac)₂	~78	Tens to hundreds micrometers	[14]
Oleylamine	Oleylamine	Oleylamine	CuCl	~63	10-30 μm	[10]
Oleylamine	Oleylamine	Oleylamine	CuBr₂/CuCl₂	16.2-90.0	20-40 μm	[15-16]
Oleylamine	Tris(trimethylsilyl) silane	Oleylamine	CuCl₂	~16.1	~17 μm	[21]

图2 不同合成条件下所得到铜纳米线的微观形貌及直径分布[16]

Fig. 2 SEM images and diameter distribution of Cu nanowires synthesized by using different halide ions[16] (a, e) 2.6 mmol Cl-; (b,f) 2.0 mmol Cl-; (c,g) 1.6 mmol Cl-; (d,h) 1.6 mmol Br-

图3 (A)铜镍双金属纳米线的SEM照片, 插图为纳米线的高分辨SEM照片; (B)铜镍双金属纳米线的暗场光学显微镜照片; (C)~(H)不同Ni含量条件下铜镍双金属纳米线的元素分布[23]

Fig. 3 (A) SEM image of Cu-Ni NWs with inset showing high resolution SEM image of Cu-Ni NWs; (B) Dark field optical microscopy images of Cu-Ni NWs; (C-H) The distribution of Cu and Ni elements of Cu-Ni NWs with different contents of nickel[23]

图4 真空抽滤后转移法(a)[35]、喷涂法(b)[36]、梅耶棒涂覆法(c)[37]和卷对卷涂覆法(d)[37]制备纳米线电极示意图

Fig. 4 Schematic diagram of the vaccum transfer method (a)[35], the spray-coating method (b)[36], the meyer rod coating method (c)[37], and the roll-to-roll coating method (d)[37]

图5 (a)~(c)等离子体后处理方法示意图; (d)经等离子体处理后相邻纳米线搭接点微观形貌; (e)基于等离子体后处理柔性导体的电路在拉伸回复条件下稳定性[48]

Fig. 5 (a-c) Schematic diagram of the experimental setup of a typical plasma treatment process; (d) SEM image of the nanowire junction after plasma treatment; (e) Current-voltage measurement of LED lamps connected by stretchable Cu NW conductors at various strains. Insets are digital photos of the whole setup at 0 and 250% strain[48]

图6 Cu NWs/PA电极的制备流程示意图(a); TiO2处理后的铜纳米线的SEM(b), TEM(c), HRTEM(d)照片和EELS (e)图谱; 处理前、H2 plasma处理以及TiO2处理后的铜纳米线薄膜拉曼图谱(f); H2热处理、H2 plasma 处理以及TiO2处理所得Cu NWs透明导电薄膜的透过率-方阻(g); 通过原位聚合转移后得到的Cu NWs/PA电极和商用的ITO/PET在弯曲104次测试中电阻变化情况(h)[53]

Fig. 6 Schematic diagram (a) of the preparation procedure of Cu NWs/PA electrode. SEM (b), TEM (c), HRTEM (d) and EELS spetra (e) of the Cu NWs film after TiO2 nanopartical sol treatment. Raman spectra (f) of Cu NWs before post-treating, after H2 plasma treatment and TiO2 nanopartical sol treatment. Plot of the transmittance (at a wavelength of 550 nm) with respect to the sheet resistance (g) for ﬁlms of Cu NWs with H2 annealing, H2 plasma treatment and TiO2 nanopartical sol treatment. Sheet resistance variation (h) of the commercial ITO/PET and Cu NWs/PA electrodes during the bending test of 104 cycles[53]

图7 (a) PET衬底上Cu纳米线电极在不同电压条件下温度随时间变化曲线; (b) PET/Cu NW/PMMA电极机械变形下电极电阻稳定性; (c)~(d)铜纳米线基可拉伸电加热元件红外照片及示意图[61]

Fig. 7 (a) Time-dependent temperature curves of Cu NW-1000 on PET films at input voltages of 1.5-5 V under ambient conditions; (b) PET/ITO transparent heaters during 104 cycles of bending tests; (c) Infrared photograph and (d) application examples of Cu NW-based stretchable heater[61]

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