Division of Inorganic and Materials Chemistry, University of Cologne, Greinstrasse 6, D-50939 Köln, Germany.
Nanoscale. 2010 Oct;2(10):2091-5. doi: 10.1039/c0nr00131g. Epub 2010 Aug 4.
Nanosized (20-30 nm) colloidal gold, silver and their alloys were obtained by reductive transformation of corresponding metal salts. Dispersions of metal nanoparticles (σ < 4%) in aqueous solutions were obtained by appropriate surface functionalization which led to inorganic inks with solid fraction ranging from 0.01-4%. Judicious choice of a polymer additive (polyethylene glycol or carboxymethyl cellulose) was found to be crucial to avoid the agglomeration of nanocrystals in the ink-jetted structures upon solvent evaporation. The versatility of the nanoparticle-based printing technology was demonstrated by fabrication of dot-matrices and circuitry patterns on different substrates. Characterization of printed structures showed a homogeneous topography (AFM) and uniform distribution of metallic nanoparticles (SEM/TEM) within the ink-jetted microdrops. The site-specific patterning on silicon (001) substrates with nanoparticle (mono)layers could also be achieved by printing the linker molecule, aminopropyltriethoxysilane, followed by selective attachment of gold nanoparticles. Positionally ordered and chemically bonded gold catalyst patterns were used for the chemical vapour deposition (CVD) of nanowires, which led to site-specific growth of nanowires via the vapour-liquid-solid (VLS) mechanism and unlike in the case of spin-coated metal colloids no significant lateral diffusion of metal nanoparticles was observed, in chemically anchored Au nanoparticles. Nanoparticle containing inks allow a user-defined dilution to vary the density of CVD grown nanowires, which was utilized to show the differences in catalytic activities of silver and gold catalysts in the VLS growth.
通过相应金属盐的还原转化，得到了纳米尺寸（20-30nm）的胶体金、银及其合金。通过适当的表面功能化，获得了金属纳米粒子（σ<4%）在水溶液中的分散体，这导致了具有 0.01-4%的固体分数的无机油墨。发现选择合适的聚合物添加剂（聚乙二醇或羧甲基纤维素）对于避免在溶剂蒸发过程中油墨喷射结构中纳米晶的团聚至关重要。基于纳米粒子的打印技术的多功能性通过在不同基底上制造点矩阵和电路图案得到了证明。打印结构的特性分析表明，在喷墨微滴内存在均匀的纳米粒子分布（SEM/TEM）和均匀的形貌（AFM）。通过打印连接分子氨丙基三乙氧基硅烷，随后选择性地附着金纳米粒子，也可以在硅（001）基底上实现纳米粒子（单）层的位点特异性图案化。通过化学气相沉积（CVD），使用位置有序且化学键合的金催化剂图案，得到了纳米线的位点特异性生长，这是通过汽-液-固（VLS）机制实现的，与旋涂金属胶体不同，在化学固定的 Au 纳米粒子中，没有观察到金属纳米粒子的明显横向扩散。含有纳米粒子的油墨允许用户定义的稀释，以改变 CVD 生长的纳米线的密度，这被用于显示银和金催化剂在 VLS 生长中的催化活性的差异。
