Ultrafast Atmospheric-Pressure-Plasma-Jet Sintering of Nanoporous TiO₂-SnO₂Composites with Features Defined by Screen-Printing

Abstract

We investigated atmospheric-pressure-plasma-jet (APPJ)-sintered nanoporous TiO 2 and TiO 2 -SnO 2 composites with patterns defined by the screen-printing technique. The pastes used for screen-printing were made of oxide nanoparticles and organic binders. After using screen-printing to define the features, APPJ was then used to rapidly sinter the screen-printed pastes. APPJ sintering for 30 s can efficiently remove the organic compounds and sinter the nanoparticles, with transmittance haze values comparable to those of nanoporous oxides prepared by conventional furnace calcination. Screen-printing is a mature scalable low-cost deposition process that has been extensively used for the fabrication of various types of devices. [1][2][3][4][5][6][7][8] In industry, this technique is commonly used in roll-to-roll processes in which printing is performed when the web is stationary. Because alignment can be more easily achieved in this technique, it is customarily used in printing the second and follow-up layers. 9,10Recently, screen-printing has attracted renewed interest owing to the search for low-cost fabrication processes for flexible/stretchable supercapacitors, 3,4 We have applied the screen-printing technique to produce ceramictype metal oxides. Screen-printing administers the pastes containing the desired oxide nanoparticles with organic solvents or binders to maintain the required viscosity. The removal of these organic compounds usually requires calcination or annealing processes that are time-consuming and require a high thermal budget. In our previous study, we have developed a rapid atmospheric-pressure-plasma-jet (APPJ) sintering process for nanoporous TiO 2 with a sintering time as short as 1 min. The sintering time can be further reduced to 30 s by introducing air-quenching to increase the oxidization ability. [21][22][23] In contrast, furnace calcination would require ∼15 min excluding the temperature ramping and cooling times. This ultrafast sintering process was made possible by the synergistic effect of highly reactive/active N 2 plasmas and heat generated in APPJs. 21,22 Most recently, we further used this sequential screen-printing and APPJ-sintering process for the fabrication of reduced graphene oxide (rGO) counter electrodes of DSSCs. The processing time was only 11 s owing to the vigorous reaction between the N 2 APPJ and the carbon-based materials; in comparison, conventional furnace calcination would take 15 min at 400• C. The estimated energy consumption per unit processing area is less than one-third that of the conventional furnace calcination process. 19In this paper, we describe the sequential screen-printing and APPJsintering processes, as well as the preparation procedure of the oxide nanoparticle pastes in detail. Nanoporous TiO 2 and TiO 2 -SnO 2 composites are sintered by APPJs and characterized. The synthesized nanoporous oxides are implemented as the photoanodes of DSSCs for functionality testing.z E-mail: jchen@ntu.edu.tw; iccheng@ntu.edu.tw ExperimentalDetails of APPJ operatio...

Atmospheric-Pressure Plasma Jet Processed Pt-Decorated Reduced Graphene Oxides for Counter-Electrodes of Dye-Sensitized Solar Cells

“…Some typical types of APPs include dielectric barrier discharge (DBD), corona discharge, atmospheric pressure plasma jets (APPJs), and microplasmas. Various plasma excitation techniques can produce APPs with different gas temperatures and charge densities; the synergetic effects of a highly energetic plasma species and temperature can achieve versatile functions in material processing [3][4][5][6][7][8][9][10][11].…”

“…The distance between the APPJ nozzle exit and the sample stage was 2 cm, and the gap between the quartz tube and the sample stage was 1 mm. More details have been described elsewhere [3,[6][7][8][9][10]24]. The substrate temperature was measured using a K-type thermocouple and recorded with a computer.…”

A Comparison Study of Furnace and Atmospheric-Pressure-Plasma Jet Calcined Pt-Decorated Reduced Graphene Oxides for Dye-Sensitized Solar Cell Application

“…The screen-printed Pt/rGO pastes were then APPJ-and/or furnacecalcined for 5, 9, 14, and 90 s. Details of the APPJ system and operation parameters were described elsewhere. 5,7,8,43,[47][48][49][50] The substrate temperature reaches ∼510 • C (as measured using a K-type thermocouple) during APPJ operation. Therefore, the furnace calcination temperature was set to 510 • C in order to compare the results.…”

Dye-sensitized solar cell utilizing TiO2–sulphur composite photoanode: influence of sulphur precursor content

“…The modifications include coating TiO 2 films with other metal oxide films such as ZnO [2], SnO 2 [3] and ZrO 2 [4,5]. TiO 2 was also prepared in the form of composite structure with another metal oxide such as TiO 2 -ZnO [6], TiO 2 -SnO 2 [7] and TiO 2 -SiO 2 [8]. It can also be prepared in the form of core-shell structure such as SnO 2 /TiO 2 and TiO 2 /ZnO, respectively [9,10].…”