染料敏化太陽能電池之染料吸收可見光轉換成電能。由於此種太陽能電池成本比半導體接合(junction)太陽能電池低，且可得到高光電轉換效率，因此受到相當的矚目。但氧化物半導體傳導帶之電子會跳回染料分子或電解液中，而使光電轉換效率降低。本研究中，試圖使用自組裝方式將金奈米粒子組裝於二氧化鈦之表面形成蕭基式能障，以減少電子跳回染料分子或電解液之機率，以增加光電轉換效率。
本實驗使用介面活性劑TOAB合成粒徑為6 nm金奈米粒子，並將金奈米粒子自組裝於二氧化鈦之表面做為染料敏化太陽能電池之蕭基式能障。金奈米粒子最大被覆率為85 %。在界面電性分析上，被覆金奈米粒子會使二氧化鈦電極之表面產生蕭基式能障。並將之組成染料敏化太陽能電池，表面電漿子可使二氧化鈦之光電轉換效率提升至0.18%。當金奈米粒子做為蕭基式能障時，以紅藥水為染料之染料敏化太陽能電池，其光電轉換效率由0.256 %提升至0.963 %。同時，亦可使葉綠素為染料之染料敏化太陽能電池光電轉換功率由0.205 %提升至0.705 %。榕樹和鴉拓草為天然植物染料之環保染料敏化太陽能電池，光電轉換效率為0.630 %和0.655 %。當使用金奈米粒子為蕭基是能障時，榕樹和鴉拓草為天然植物染料之環保染料敏化太陽能電池光電轉換效率更可達1.180 %和1.490 %。

Dye converses visible light into photoelectric power in dye-sensitized solar cell (DSSC), which is more inexpensive than junction semiconductor solar cell. However the transportation of concentration-driven electron is slow between the dye and electrode without the Schottky barrier in DSSC. When an electron in the dye passes the Au thin layer through tunneling to the conduction band of the TiO2, it is unable to go back to either the dye or the electrolyte due to the Schottky barrier. In this study, we synthesized 6 nm Au nanoparticles by surfactants-TOAB and fabricated on the surface of TiO2 layer as the electrode of DSSC by self-assembly method. The maximum coverage of Au nanoparticles on the surface of TiO2 layer is 85 . The Schottky barrier is formed between the Au nanoparticles and TiO2 layer. Besides, surface plasmon resonance induces photoexcited electron to TiO2 layer. Efficiency of conversion is 0.18 . When Au nanoparticles act as the Schottky barrier, efficiency of photoelectric conversion for mercurochrome increases from 0.26 to 0.96 %. Efficiency of photoelectric conversion for chlorophyll yields from 0.205% up to 0.705 %. When Ficus Reusa Linn and Rhoeo spathacea(Sw.) Stearn act as natural dyes in green DSSC, efficiencies of photoelectric conversion are 0.630 % and 0.655 %, respectively. When Au nanoparticles act as the Schottky barrier in green DSSCs, efficiencies of photoelectric conversion yield up to 1.180 % and 1.490 %.

參考文獻
[1] L. J. Sherry, S. -H. Chang, G. C. Schatz, R. P. V. Duyne, B. J. Wiley, Y. Xia, "Localized Surface Plasmon Resonance Spectroscopy of Single Silver Nanocubes”, Nano Lett. 5, 2034-2038 (2005).
[2] E. -S. Kwak, J. Henzie, S. -H. Chang, S. K. Gray, G. C. Schatz, T. W. Odom, "Surface Plasmon Standing Waves in Large-Area Subwavelength Hole Arrays”, Nano Lett. 5, 1963 (2005).
[3] S. -H. Chang, S. K. Gray, and G. C. Schatz, "Surface Plasmon Generation and Light Transmission by Isolated Nanoholes and Arrays of Nanoholes in Thin Metal Films”, Opt. Express 13, 3150-3165 (2005).
[4] C. Hubert, A. Rumyantseva, G. Lerondel, J. Grand, S. Kostcheev, L. Billot, A. Vial, R. Bachelot, P. Royer , S. -H. Chang, S. K. Gray, G. P. Wiederrecht, G.C. Schatz, “Near-field Photochemical Imaging of Noble Metal Nanostructures”, Nano Lett. 5, 615-619 (2005).
[5] L. Yin, V. K. Vlasko-Vlasov, A. Rydh, J. Pearson, U. Welp1, S. -H. Chang, S. K. Gray, G. C. Schatz, D. E. Brown, C. W. Kimball, “Surface Plasmons at Single Nanoholes in Au-films”, Appl. Phys. Lett. 85, 467-469 (2004).
[6] S. Link, M. A. El-Sayed, “Spectral Properties and Relaxation Dynamics of Surface Plasmon Electronic Oscillations in Gold and Silver nanodots and Nanorods”, J. Phys. Chem. B 103, 8410-8426 (1999).
[7] R. Jin, Y. C. Cao, C. A. Mirkin, K. L. Kelly, G. C. Schatz, J. G. Zheng, “Photoinduced Conversion of Silver Nanospheres to Nanoprisms”, Science 294, 1901-1903 (2001).
[8] J. J. Mock, M. Barbic, D. R. Smith, D. A. Schults, S. J. Schults, “Plasmon Resonance of Individual Colloidal Silver Nanoparticles”, J. Chem. Phys. 116, 6755-6759 (2002).
[9] E. A. Stern, R. A. Ferrell, “Predicted Radiation of Plasmon Oscillation in Metal Films”, Phys. Rev. 111, 1214-1222 (1958).
[10] R. H. Ritchie, H. B. Eldridge, “Optical Emission from Irradiated Foils”, Phys. Rev. 126, 1935-1947 (1962).
[11] M. Grätzel, “Applied physics: Solar cells to dye for”, Nature 421, 586-587 (2003).
[12] K. Tennakone, P. K. M. Bandaranayake, P. V. V. Jayaweera, A. Konno, G. R. R. A. Kumara, “Dye-sensitized Composite Semiconductor Nanostructures”, Physica E 14, 190-196 (2002).
[13] E. W. McFarland and J. Tang, “A photovoltaic device structure based on internal electron emission”, Nature 421, 616-618 (2003).
[14] G. M. Whitesides, B. Grzyboski, “Molecular Self-Assembly papers • Beyond molecules: Self-assembly of mesoscopic and macroscopic components”, Science 295, 2418-2421 (2002).
[15] M. Brust, M. Walker, D. Bethell, D. J. Schiffrin, R. Whyman, “Synthesis of Thiol-derivatised Gold Nanoparticles in a Two-Phase Liquid-Liquid System”, J. Chem. Soc. Chem. Commun. 5 , 801-802 (1994).
[16] V. F. Puntes, K. M. Krishnan, A. P. Alivisatos, “Colloidal Nanocrystal Shape and Size Control: The Case of Cobalt.“ , Science 291, 2115-2117 (2001).
[17] L. Guo, Q. Huang, X. -Y. Li, S. Yan, ”Iron Nanoparticles: Synthesis and Applications in Surface Enhanced Raman Scattering and Electrocatalysis.”, Phys. Chem. Chem. Phys. 3, 1661-1665 (2001).
[18] S. -J. Park, S. Kim, S. Lee, Z. G. Khim, K. Char, T. Hyeon, “Synthesis and Magnetic Studies of Uniform Iron Nanorods and Nanospheres.”, J. Am. Chem. Soc. 122, 8581-8582 (2000).
[19]郭清癸、黃俊傑、牟中原， ”金屬奈米粒子的製造”, 物理雙月刊（廿三卷六期）, 614-624 (2001年12月).
[20] Y. H. Su, L. G. Teoh, W. H. Lai, S. -H. Chang, H. –C. Yang, and M. H. Hon, “Ellipsometric Advances for Local Surface Plasmons Resonance to Determine Chitosan Adsorption on Layer-by-layer Gold Nanoparticles”, Appl. Spectrasc. (in press).
[21] Y. H. Su, W. H. Lai, L. G. Teoh, M. H. Hon, J. L. Huang, “Layer-by-layer Au Nanoparticles as a Schottky Barrier in Water-based Dye-sensitized Solar Cell”, Appl. Phys. A: Mater. Sci. & Proc. 88, 173-178 (2007).
[22] C. Ritchie, “Plasma Losses by Fast Electrons in Thin Films”,Phys. Rev. 106, 874-881 (1957).
[23] C. F. Borhren, D. R. Huffman, “Absorption and Scattering of Light by Small Particles”, Wiley-Interscience, Chap.4, 1988.
[24] Y. S. Shon, S. M. Gross, B. Dawson, M. Porter, R. W. Murray, “Alkanethiolate Protected Gold Clusters Generated from Sodium S-dodecylthiosulfate (Bunte Salts)”, Langmuir 16, 6555-6561 (2000).
[25] J. C. Maxwell-Garnet, “Colors in Metal Glasses and in Metallic Films”, Philos. Trans. R. Soc. A 203, 385-420 (1904).
[26] Y. Tain, T. Tatauma, “Mechanisms and Applications of Plasmon-Induced Charge Separation at TiO2 Films Loaded with Gold Nanoparticles”, J. Am. Chem. Soc. 127, 7632-7637 (2005).
[27] C. Kittel, “Introduction to Solid State Physics”, John Wiley & Sons Canada (1976), p.239-247.
[28] B. O'Regan, M. Graetzel, “A Low-cost, High-efficiency Solar Cell Based on Dye-sensitized Colloidal TiO2 Films”, Nature 353, 737-739 (1991).
[29] A. Kay, M. Grätzel, “Photosensitization of Titania Solar Cells with Chlorophyll Derivatives and Related Natural Porphyrins”, J. Phys. Chem. 97, 6272-6277 (1993).
[30] G.P. Smestad, M. Grätzel, “Demonstrating Electron Transfer and Nanotechnology: a Nature Dye-sensitized Nanocrystalline Energy Converter”, J. Chem. Educ. 75, 752-756 (1998).
[31] B. R. Speer, “Photosynthetic Pigments" in UCMP Glossary (online). University of California, Berkeley Museum of Paleontology (2007).
[32] H. Saito, S. Uegusa, T. N. Murakami, N. Kawashima, and T. Miyasaka, “Fabrication and Efficiency Enhancement of Water-based Dye-Sensitized Solar Cells by Interfacial Activation of TiO2 Mesopores”, Electrochemistry, 72, 310-316(2004).
[33] G. P. Smestad, “Optoelectronics of Solar Cells”, SPIE-The International Society for Optical Engineering Bellingham Washington (2002), p. 19-21.
[34] D. Roy, J. Fendler, “Reflection and Absorption Technology for Optical Characterization of Chemically Assembled Nanomaterials”, Adv. Mater. 16, 479-508 (2004).
[35] Y. H. Su, W. H. Lai, S. -H. Chang, M. H. Hon, “Surfactants-aided Syntheses of Different Sizes and Triangular Shape of Gold Particles Using Trisodium Citrate in Environmentally Friendly and Photoinduced Methods”, Journal of Nanosci. and Nanotechnol. (in press).
[36] H. -L. Zhang, S. D. Evans, J. R. Henderson, ”Spectroscopic Ellipsometric Evaluation of Gold Nanoparticle Thin Films Fabricated by Layer-by-Layer Self-Assembly”, Adv. Mater. 15, 531-534 (2003).
[37] Y. H. Su, W. H. Lai, W.-Y. Chen, M. H. Hon, S.-H. Chang, “Surface Plasmon Resonance of Gold Nano-sea-urchin”, Appl. Phys. Lett. 90, 181905 (2007)
[38] M. Fox, “Optical Properties of Solids”, Oxford University Press (2001), p. 3-6.
[39] S. Hao, J. Wu, Y. Huang, J. Lin, “Natural Dyes as Photosensitizers for Dye-sensitized Solar Cell”, Solar Energy 80, 209 (2006).
[40] A.S. André, S. Polo, N. Yukie, M. Iha, “Blue Sensitizers for Solar Cells: Natural Dyes from Calafate and Jaboticaba”, Solar Energy Mater. & Solar Cells 90, 1936 (2006).
[41] Q. N. Lu, Q. Yang, H. W. Zou, “Effects of Cerium on Accumulation of Anthocyanins and Expression of Anthocyanin Biosynthetic Genes in Potato Cell Tissue Cultures”, J. Rar. Eart. 24, 479-484 (2006).