Formulation of an Aqueous Titania Suspension and its Patterning with Ink‐Jet Printing Technology

Abstract

We present a general protocol for processing cost‐beneficial, environmentally benign aqueous‐type suspensions containing metal‐oxide nanostructured particles, and their patterning with piezoelectric ink‐jet printing technology. The critical issues relevant to ink‐jet printing are the preparation and stabilization of nanosized particles in a fluid and adjusting its physical properties to the values appropriate for a particular ink‐jet printer mechanism. We discuss and illustrate, on a model titania system, the processing of a highly stable, colloidal, water‐based suspension containing particles not bigger than 570 nm, prepared by a ball‐milling process. For the ink‐jet printing experiments, the surface tension and the viscosity of the suspension were modified by the addition of a small amount of the appropriate non‐ionic amphiphiles and glycerol. The formation of droplets, their positioning on the substrate, and the shape and uniformity of the dots on the substrate are discussed and correlated with the fluid properties via the inverse Ohnesorge number Z. It was shown successfully that uniform, regular‐shaped TiO2 dots with a diameter of 30 μm and a good positioning accuracy on Si/SiO2 substrates could be obtained by jetting a fluid with Z values of 5 and 9 using a piezoelectric ink‐jet printer with a nozzle diameter of 21 μm operating at an amplitude of 13 V and a frequency of 5 kHz.

Effect of Ionic Compounds of Different Valences on the Stability of Titanium Oxide Colloids

“…It was also discovered that the shape [18] of the titania particles and the ionic environment [19] influences the photocatalytic activity. Moreover, novel titanium oxide-based substances were applied in solar cells [20], electrode materials [21], supercapacitors [22], inks [23] and electronics [24].…”

Inkjet Printing of Titanium Dioxide Photoanodes for Dye Sensitized Solar Cells

“…The literature pertaining to inkjet depositions of TiO 2 has focused on depositions of TiO 2 suspensions for the formation of TiO 2 layers with a uniform density [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. No consistent TiO 2 suspension formulations have been reported for inkjet printing with the exception of Deionized (DI) water as a primary solvent.…”

“…Figure 2 shows an example of a particle size distribution as a percentage of total volume for various milling times of a suspension containing 15 vol% of TiO 2 particles suspended in water [8]. The nature of the milling equipment and the milling speed largely determine the effectiveness of attrition milling.…”

“…This ratio has been reported as 50:1 [8]. Solutions to the Naveir-Stokes equation can express these parameters as a single number known as the inverse Ohnesorge number, Z:…”

“…A relatively novel approach for the deposition of TiO 2 films through the use of inkjet printing has begun to attract attention owing to its high level of control over the process and the possibility of direct patterning of layers [8,9]. Specialty laboratory printers designed for printing of solutions with a wide variety of fluid properties are available and have been used for TiO 2 depositions.…”