Natural Sensitizer for Dye-Sensitized Solar Cells Using Three Layers of Photoelectrode Thin Films with a Schottky Barrier

Abstract

Problem statement: This study combines Au nanoparticles with TiO 2 nanoparticles to form a Schottky barrier and applies it to the photoelectrode thin film of Dye-Sensitized Solar cells (DSSCs). Approach: First, commercial TiO 2 powder (Degussa P25) was put into the alkaline solution to prepare TiO nanotubes (Tnt) by a hydrothermal process. Tnt were sintered at 550° to obtain TntC550 particles and fabricated into a translucent sol by two hydrothermal treatments and baked at 180° to acquire H180 particles. H180 and TntC550 were spread into transparent polymer films by a doctor blade. H180 serves as the first layer and TntC550 the second, with both were sintered at 450°. The third layer uses hydrogen tetrachloroautate (HAuCl 4) and trisodium citrate (C 6 H 5 Na 3 O 7) to prepare Au nanoparticles by salt reduction. Natural dyes of bougainvillea leaves for chlorophyll and blueberries for anthocyanin were employed in this study. Extracted chlorophyll and anthocyanin dyes were also blended in the proportion of 1: 1 as a mixed dye and these three different natural dyes were compared to compare their photoelectric conversion efficiencies. Electrolyte and counter electrode (Pt) were added to form the sandwich structure of DSSCs. After being sealed, DSSCs were tasted for fill factor, photoelectric conversion efficiency and incident photon-to-current conversion efficiency. Results: Spherical Au nanoparticles around 27nm were adhered to the TntC550 make a film by self-assembly to complete the preparation of the third of photoelectrode thin film of DSSCs. Results from the experimental tests show that for the dye mixtures, photoelectric conversion efficiency of DSSCs in this study can reach 0.75% with the V OC of 0.56 V and J SC of 2.93 mA/cm 2 and FF of 0.47. Conclusion: It can be seen from the current density logarithm and voltage diagram that the prepared Au nanoparticles produce Schottky barriers on the surface of TiO 2. Due to the Schottky barrier, electrons were unable to go back to the dye molecules or electrolyte, thus effectively enhancing the electronic conversion efficiency.

Performances of spin coated silver doped ZnO photoanode based dye sensitized solar cell

“…The photoelectrode have semiconductor oxide layer like ZnO, TiO 2 and dye adsorbed into semiconductor oxide layer. On the other side, platinum or graphite acts as counterelectrode and iodine as redox couple electrolyte [4][5][6][7][8]. Transparent conducting oxide coated glass like ITO has been the main choice for the substrate material for the DSSC, due to its excellent op-tical, electrical and encapsulation barrier properties.…”

Dye-Sensitized Solar Cell Using Saffron Petal Extract as a Novel Natural Sensitizer

“…Considering other similar DSSCs the J sc of 2.3 mA/cm 2 is high and the fill factor of 0.71 is noticeably high [29,[35][36][37][38][39][40]. The good J sc may be due to the capability of the sensitizer to absorb sunlight over a wider region of the solar spectrum, and the higher power conversion efficiency, which is fairly good in comparison with the other similar studies [29,36,38,[41][42][43][44][45][46]. The high fill factor shows a low equivalent series resistance and high equivalent shunt resistance [47] and it can be related to the good sensitization properties of saffron petal dye extract.…”

Chlorophyll as Photosensitizer in Dye-Sensitized Solar Cells

“…Chang et al [17] have investigated the plasmonic effect of gold (Au) nanoparticles with an average size of 27 nm in TiO 2 DSSC using chlorophyll from bougainvillea leaves. An efficiency of 0.618% was obtained.…”