Rapid Atmospheric Pressure Plasma Jet Processed Reduced Graphene Oxide Counter Electrodes for Dye-Sensitized Solar Cells

Abstract

In this work, we present the use of reduced graphene oxide (rGO) as the counter electrode materials in dye-sensitized solar cells (DSSCs). rGO was first deposited on a fluorine-doped tin oxide glass substrate by screen-printing, followed by post-treatment to remove excessive organic additives. We investigated the effect of atmospheric pressure plasma jet (APPJ) treatment on the DSSC performance. A power conversion efficiency of 5.19% was reached when DSSCs with an rGO counter electrode were treated by APPJs in the ambient air for a few seconds. For comparison, it requires a conventional calcination process at 400 °C for 15 min to obtain comparable efficiency. Scanning electron micrographs show that the APPJ treatment modifies the rGO structure, which may reduce its conductivity in part but simultaneously greatly enhances its catalytic activity. Combined with the rapid removal of organic additives by the highly reactive APPJ, DSSCs with APPJ-treated rGO counter electrode show comparable efficiencies to furnace-calcined rGO counter electrodes with greatly reduced process time. This ultrashort process time renders an estimated energy consumption per unit area of 1.1 kJ/cm(2), which is only one-third of that consumed in a conventional furnace calcination process. This new methodology thus saves energy, cost, and time, which is greatly beneficial to future mass production.

Rapid Atmospheric-Pressure-Plasma-Jet Processed Porous Materials for Energy Harvesting and Storage Devices

“…The sintering time for TiO2 nanoparticles could be as short as 30 s with a substrate temperature of ~300 °C (heated by APPJs, no external heating source was used) [24]. For producing porous rGO nanosheets, the sintering time was merely 11 s [27]. The schematic of APPJ apparatus is shown in Figure 1a.…”

“…Finally, the mixture is concentrated using a rotary concentrator. Figure 3 shows the representative optical emission spectra (OES) and snapshots of APPJs during the APPJ-sintering processes for rGO pastes [27]. It is noted that the case is simpler when sintering screen-printed pastes containing oxide nanoparticles instead of rGOs because the main reaction occurs between the APPJs and organic binders only.…”

“…SEM images of rGOs [27], nanoporous SnO2, Y2O3, and TiO2/SnO2 sintered by APPJs for various durations. Figure 4 shows SEM images of the nanoporous oxides and 3D rGO nanosheets prepared using the rapid APPJ sintering technique [27]. The APPJ-sintered 3D rGO nanosheets are porous with some sharp edges revealed.…”

“…An ultrafast (30 s-1 min) APPJ sintering process on nanoporous TiO2 photoanodes of DSSCs has been promisingly developed; these DSSCs showed efficiency comparable to those fabricated by conventional furnace calcination process (510 °C × 15 min) [24][25][26]. A similar APPJ sintering process was also applied for producing 3D reduced graphene oxide (rGO) nanosheet counter electrodes of DSSCs; the required processing time was only 11 s [27].…”

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

“…19 In 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.…”