Photonic crystals in biology - NanoTR-VI

Poster Session, Thursday, June 17 Theme F686 - N1123Enhanced Photocatalytic Activity Of Dye-Sensitized SolarCells With Optimized CathodeBerk H. Giray a , Hermann Tempel b,c , Saygin Aras c , Özlem Soydas c , Jörg J.Schneider b , and Deniz Üner c,*a Aselsan Inc., 06172, Ankara / TURKEYb Eduard-Zintl Institut Technische Universität Darmstadt, Petersenstrasse 18 64287 Darmstadt, GERMANYc Middle East Technical University, Chemical Engineering Department, 06531, Ankara / TURKEY*uner@metu.edu.trAbstract. In this study the effect of CNT modified TiO 2 thin films on the performance of Dye Sensitized SolarCells (DSSC) is studied. Furthermore, the effect of the thermal decomposition temperature of Pt layer on thecathode surface was also investigated. The CNT loadings and Pt decomposition temperatures were optimized forthe efficiencies of the DSSCs.Keywords: dye sensitized solar cells, carbon nanotubes, Pt loadings, metal support interaction.PACS: 81.40.Tv - Optical and dielectric properties related to treatment conditions:http://www.aip.org/pacs/index.htmlINTRODUCTIONSince the introduction of DSSC from Grätzel andO’Regan [1] , numerous studies have been done tooptimize the working electrode. But still theefficiencies are limited to less than 10-15% [2] . Themajority of the studies focus on the anode side of theDSSCs. However, there is also room for improvementin the catalysis going on at the Pt nanoparticles overthe cathode surface.EXPERIMENTALPt layer was coated by brushcoating of platisol(Solaronix Switzerland). After coating the platinumprecursor was decomposed by heat treatment at 400°Cfor 5 min. Afterwards sintering at temperatures from400°C to 550°C were applied. The working electrode(anode) was prepared by doctor blade technique. Theprecursor solution was Ti-Nanoxide T20 (Solaronix)was the choice of anatase. It is a paste containing 11weight % anatase with uniform particle diameter of 20nm.CNTs were incorporated into the working electrodeTiO 2 by stiring ethanol, anatase nanopowder,tetratitaniumisopropoxide, nitric acid, polyethyleneglycoland pluronic at 50°C for 20h. This sol wasapplied onto the FTO glass slides by spincoatingtechnique [3] .RESULTS AND DISCUSSIONThe amount of Ru-Dye [Solaronix Ru-535]adsorbed increased upon incorporation of activatedcarbon on the anode. But, it should be rememberedthat a larger amount of dye not always leads to highercurrent in the DSSC. Figure 1 shows the TiO 2 layerwith incorporated CNTs.The effects of the different sintering parameters on thecathode surface morphology were reported in terms ofthe effect on the cell efficiency and the fill factor inTable 1. It is seen that the catalytic I - /I 3 - reactions atthe cathode side is influenced by the Pt particle sizes.Further characterization is in progress.FIGURE 1. SEM image of TiO 2 film withincorporated CNTs.TABLE 1. Effect of different annealing conditions onthe cell performance [4]particles size P FF ηT( o C) (nm)(mW) (%)none 89 24,50 0.454 2.36450 83 25,80 0.466 2.48500 69 29,60 0.471 2.85550 67 30,00 0.474 2.89ACKNOWLEDGMENTSFinancial support of BMBF Germany andTUBITAK (107M447) Inten-C joint program andTUBITAK (108M631) is acknowledged. METUCentral laboratories and the Metallurgical andMaterials Engineering Department are kindlyacknowledged for the SEM measurements.REFERENCES1. Grätzel and O’Regan, Nature, 353, 1991, 737.2. Hodes G. Electrochemistry of nanomaterials, VCH-Wiley, Weinheim, 2000.3. H. Itai, H. et al. Chemistry Letters,No. 9, 37, 2008, 940.4. H. B. Giray M.S Thesis, 2010, METU, Ankara.6th Nanoscience and Nanotechnology Conference, zmir, 2010 1