Nanoparticle inks should allow simple low-cost manufacture but the nanoparticles usually used are surrounded in non-conductive ligands – molecules that are introduced during synthesis for stabilising the particles. These ligands must be removed by annealing to make the ink conducting.
The gold nanoparticles have a resistivity of around 9 x 10-6 Ωcm – similar to pure gold. The researchers used the nanoparticle ink to print organic thin film transistors on a flexible polymer and a paper substrate at room-temperature, producing devices with mobilities of 7.9 and 2.5cm2V-1s-1 for polymer and paper respectively.
Researchers concluded “This room-temperature printing process is a promising method as a core technology for future semiconductor devices.”