High Performance Quasi-Solid Dye-Sensitized Solar Cells with Nano Clay Electrolyte
- PDF / 566,807 Bytes
- 4 Pages / 612 x 792 pts (letter) Page_size
- 104 Downloads / 157 Views
1211-R09-04
High Performance Quasi-Solid Dye-Sensitized Solar Cells with Nano-clay Electrolyte Tomoyuki Inoue,1 Satoshi Uchida, 1 Takaya Kubo1 and Hiroshi Segawa1 1
Research Center for Advanced Science and Technology (RCAST), The University of Tokyo
4-6-1, Komaba, Meguro, Tokyo 153-8904, JAPAN
ABSTRACT An artificial nano-clay powder was newly examined as an electrolyte gelator for quasisolid-state dye-sensitized solar cell (DSSC). The size of the clay has two main distributions (1.4 nm and 20 nm in diameter) as confirmed by FE-SEM and STEM observation. The gelation point was determined by using a rheometer. The gel state was maintained with >5 wt% nano-clay in the acetonitrile based solvent. The quasi-solid-state DSSC with 10 wt% nano-clay electrolyte successfully showed a high photoelectric conversion efficiency of 10.3%, which is equivalent to that using a liquid electrolyte. INTRODUCTION The dye-sensitized solar cells (DSSCs) introduced by Grätzel in 1991 have received great attention over the past decade because of their potential for high energy conversion efficiency and low production cost [1,2]. However, the presence of liquid electrolytes in such modules may result in some practical limitations of sealing and long-term stability due to the leakage of the liquid electrolyte. According to the previous reports, gelation of organic solvent based liquid electrolytes with low molecular mass organogelators (LMOGs), polymers, or nanoparticles can produce quasi-solid-state electrolytes for DSSCs. Nevertheless, in most of cases, the cell performance tends to decrease with these gelators because of the low ionic conductivity and poor electrolyte/electrode interface contact [3-5]. Nanosize inorganic materials such as silica, titania, etc. have also been examined as gelators [6-8]. Recently, DSSCs with quasi-solid-state electrolyte with clay mineral have been proposed [9-14]. The clay powder is attractive for its abundance in nature, high chemical stability and also because it is non-hazardous to humans. Moreover, clay dispersed liquid shows thixotropic properties and is widely used in industry such as paint, cement, cosmetics, as a conventional gelator. However, according to these reports, the cell performances are still low because they have only used naturally occurring minerals. The thickness of the primary particle may reach about 1 nm but the size will be more than 100 nm in diameter. This is why the natural clay particle can not sufficiently penetrate into the porous TiO2 layers. They can only accumulate on the topmost TiO2 film surface and absorb the excess amount of electrolyte. In this point of view, our synthesized ultra-fine clay powder is promising for real quasi-solid electrolyte. EXPERIMENT
The liquid electrolyte composition is 0.1 M LiI, 0.6 M 1-butyl-3-methylimidazolium iodide, 0.03 M I2, 0.5 M tert-butylpyridine (TBP), and 0.1 M guanidinium thiocyanate in acetonitrile. The quasi-solid electrolytes (clay electrolyte) were prepared by adding clay powder with various weight ratios into the liquid ele
Data Loading...
