Inkjet printing of high-concentration particle-free platinum inks

An investigation into the optimisation of a highly-concentrated (20 wt%) and stable platinum (Pt) organometallic ink, showing consistent jetting performance whilst minimising the negatives associated with particle-containing inks. The ink was synthesised and printing demonstrated onto glass by a piezoelectric drop-on-demand inkjet printer. Stable and rapid jetting (Z number: 1.83, 8 m/s) was achieved using cyclohexanol-based viscosity modifiers and optimisation of the print settings. Uniform nanofilms (10 – 30 nm) were obtained by the printing of successive layers which showed high conductivities (1.6 ± 0.13 × 10 ⁶S/m, 17% of bulk Pt). The 20 wt% concentrated inks showed increased uniformity and electrical conductivity over previously reported 10 wt% equivalent inks, enabling for the first-time conductive features with a single print pass. High quality films were deposited by increasing the printed thickness due to significant uniformity improvements obtained across the centre of the printed films. A high film purity was demonstrated by X-ray diffraction, Scanning Electron Microscopy and Energy Dispersive X-rays. The suitability of the printed Pt films for production of Surface Enhanced Raman Scattering (SERS) detection platforms was also investigated. The presented work will pave the way for applications benefiting from selective deposition and low reactivity Pt nanofilms, as a proof of concept an LED circuit is demonstrated.