Inkjet printing of metal nanoparticles allows for design flexibility, rapid processing and enables the 3D printing of functional electronic devices through co-deposition of multiple materials. However, the performance of printed devices, especially their electrical conductivity, is lower than those made by traditional manufacturing methods and is not fully understood. Here, we reveal that anisotropic electrical conductivity of printed metal nanoparticles is caused by organic residuals from their inks. We employ a combination of electrical resistivity tests, morphological analysis and 3D nanoscale chemical analysis of printed devices using silver nanoparticles to show that the polymer stabiliser polyvinylpyrrolidone tends to concentrate between vertically stacked nanoparticle layers as well as at dielectric/conductive interfaces. Understanding the behaviour of organic residues in printed nanoparticles reveals potential new strategies to improve nanomaterial ink formulations for functional printed electronics.

金属纳米颗粒的喷墨印刷可实现设计灵活性，快速处理，并通过多种材料的共沉积实现功能性电子设备的3D打印。然而，印刷设备的性能，特别是其电导率，低于传统制造方法所制造的性能，并且尚未完全被理解。在这里，我们揭示了印刷金属纳米粒子的各向异性电导率是由其油墨中的有机残留物引起的。我们结合了使用银纳米颗粒的印刷设备的电阻率测试，形态分析和3D纳米级化学分析的组合，以显示聚合物稳定剂聚乙烯吡咯烷酮倾向于集中在垂直堆叠的纳米颗粒层之间以及介电/导电界面处。