植物體具有相當良好的光電轉換系統可以把光能百分百轉換並儲存。除了歸功於精確的分子與酵素間的作用，植物蘊含的色素分子對高光電效率也具有相當貢獻，亦相當便宜且隨處可得。有鑑於此，發展植物色素做為染料敏化太陽電池的替代昂貴釕染料是一個相當具有潛力的研究方向。
本研究內容即從微觀的角度分別探討天然色素，葉綠素a(chlorophyll a)及其衍生分子二氫卟吩(chlorin)、還有矢車菊花青素(cyanidin)。利用密度泛函理論(density functional theory, DFT)原理與方法，模擬計算葉綠素與花青素染料分子的結構特性與光電性質，並做進一步的探討以及預測分析。建立天然色素chlorophyll a、chlorin和cyanidin的原子模型後，利用此模型進行結構最佳化、分子間共振頻率、單點能量等一系列計算，最後分析模擬計算的結果即可得到分子能量(molecular energies)、熱化學分析(thermochemical properties)、分子軌域(molecular orbital)、能隙(band gap)、紫外線可見光譜(UV/VIS spectrum)等所需數據。此外，染料分子的溶劑效應以及pH值等影響也一併計算分析。
在實驗部分使用紫外可見光度計（UV/VIS spectrophotometer）量測由榕樹萃取出之葉綠素以及紫色甘藍菜萃取之花青素，與模擬計算的紫外可見吸收光譜圖比對後，其結果都是相符的。本論文進而利用計算量子化學分析葉綠素和花青素對於電極的吸附以及電子注入等輸送狀況，找出葉綠素與矢車菊花青素內部電子躍遷至光電極的路徑不連續，是造成生物色素太陽電池效能偏低之真正原因，並提出未來改進方式，達到高科技、低成本、高效率太陽電池目標。

[1] http://www.renewablesb2b.com/data/ahk_saudi_arabia/downloads/files/Schott.pdf
[2] B. Q. Liu, X. P. Zhao and W. Luo, “The synergistic effect of two photosynthetic pigments in dye-sensitized mesoporous TiO2 solar cells”, Dyes and Pigments, Vol. 76, pp. 327-331, 2008
[3] http://www.ipama-age.org/news/A20081204.html
[4] http://www.tsipo.com/analysis/dssc_electrode.html
[5] H. Tsubomura, M. Matsumura, Y. Nomura and T. Amamiya, “Dye sensitized zinc oxide: aqueous electrolyte : platinum photocell”, Nature, Vol. 261, pp. 402-403, 1976
[6] B. O’Regan and M. Grätzel, “A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films”, Nature, Vol. 353, pp. 737-740, 1991
[7] M. K. Nazeeruddin, P. Pe´chy, T. Renouard, S. M. Zakeeruddin, R. Humphry-Baker, P. Comte, P. Liska, L. Cevey, E. Costa, V. Shklover, L. Spiccia, G. B. Deacon, C. A. Bignozzi and M. Grätzel, “Engineering of efficient panchromatic sensitizers for nanocrystalline TiO2-based solar cells”, J. Am. Chem. Soc, Vol. 123, pp. 1613-1624, 2001
[8] M. K. Nazeeruddin, F. D. Angelis, S. Fantacci, A. Selloni, G. Viscardi, P. Liska, S. Ito, B. Takeru and M. Grätzel, “Combined experimental and DFT-TDDFT computational study of photoelectrochemical cell ruthenium sensitizers”, J. AM. CHEM. SOC, Vol. 127, pp. 16835-16847, 2005
[9] C. Qin and A. E. Clark, “DFT characterization of the optical and redox properties of natural pigments relevant to dye-sensitized solar cells”, Chemical Physics Letters, Vol. 438, pp. 26-30, 2007
[10] A. Mishra, M. K. R. Fischer and Peter Bäuerle, “Metal-free organic dyes for dye-sensitized solar cells: from structure: property relationships to design rules”, Angew. Chem. Int. Ed, Vol. 48, pp. 2474-2499, 2009
[11] S. Hao, J. Wu, Y. Huang and J. Lin, “Natural dyes as photosensitizers for dye-sensitized solar cell”, Solar Energy, Vol. 80,pp. 209-214, 2006
[12] X. F. Wang, Y. Koyama, O. Kitao, Y. Wada, S. I. Sasaki, H. Tamiaki and H. Zhou, “Significant enhancement in the power-conversion efficiency of chlorophyll co-sensitized solar cells by mimicking the principles of natural photosynthetic light-harvesting complexes”, Biosensors and Bioelectronics, Vol. 25, pp. 1970-1976, 2010
[13] K. Tennakone, A. R. Kumarasinghe, G. R. R. A. Kumara, K. G. U. Wijayantha and P. M. Sirimanne, “Nanoporous TiO2 photoanode sensitized with the flower pigment cyanidin”, Journal of Photochemistry and Photobiology A: Chemistry, Vol. 108, pp. 193- 195, 1997
[14] N. Cherepy, G. P. Smestad, M. Grätzel and J. Zhang, “Ultrafast electron injection: implications for a photoelectrochemical cell utilizing an anthocyanin dye-Sensitized TiO2 nanocrystalline electrode”, J. Phys. Chem. B, Vol. 101, pp. 9342-9351, 1997
[15] K. Wongcharee, V. Meeyoo and S. Chavadej, “Dye-sensitized solar cell using natural dyes extracted from rosella and blue pea flowers”, Solar Energy Materials and Solar Cells, Vol. 91, pp. 566-571, 2007
[16] J. M. R. C.Fernando and G. K. R. Senadeera, “Natural anthocyanins as photosensitizers for dye-sensitized solar devices”, Current Science, Vol. 95, pp. 663-666, 2008
[17] A. Kay and M. Grätzel, “Artificial photosynthesis. 1. photosensitization of TiO2 solar cells with chlorophyll derivatives and related natural porphyrins”, J. Phys.Chem, Vol. 97, pp. 6272-6277, 1993
[18] X. F. Wang, H Tamiaki, L. Wang, N. Tamai, O. Kitao, H. Zhou and S. I. Sasaki, “Chlorophyll-a derivatives with various hydrocarbon ester groups for efficient dye-sensitized solar cells: static and ultrafast evaluations on electron injection and charge collection processes”, Langmuir, Vol. 26, pp. 6320-6327, 2010
[19] X. F. Wang, C. H. Zhan, T. Maoka, Y. Wada and Y. Koyama, “Fabrication of dye-sensitized solar cells using chlorophylls c1 and c2 and their oxidized forms c’1 and c’2 from Undaria pinnatifida (Wakame)”, Chemical Physics Letters, Vol. 447, pp. 79-85, 2007
[20] H. Chang, H. M. Wu, T. L. Chen, K. D. Huang, C. S. Jwo and Y. J. Lo, “Dye-sensitized solar cell using natural dyes extracted from spinach and ipomoea”, Journal of Alloys and Compounds, Vol. 495, pp. 606-610, 2010
[21] http://web2.cc.nctu.edu.tw/~wfgore/qu1.html
[22] 蔡佳妘(洪哲文指導), “Ⅲ-N族半導體量子點之LED光電特性量子模擬與光學測試”, 清華大學動力機械系碩士論文, 2010.
[23] M. A. L. Marques, “Time-dependent density functional theory”, Berlin: Springer, 2006.
[24] A. D. Becke, “Density-functional thermochemistry. III. The role of exact exchange”, J. Chem. Phys, Vol. 98, pp. 5648-5652, 1993
[25] C. Lee, W. Yang and R. G. Parr, “Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density” , Phys. Rev. B, Vol. 37, pp. 785-89, 1988
[26] W. J. Herre, R. Ditcrfield and J. A. Pople, “Self-consistent molecular orbital methods. XII. Further extensions of gaussian-type basis sets for use in molecular-orbital studies of organic molecules”, J. Chem. Phys, Vol. 56, pp. 2257, 1972
[27] http://www.gaussian.com/
[28] M. Grätzel, “Recent advances in sensitized mesoscopic solar cells”, Accounts of Chemical Research, Vol. 42, pp. 1788-1798, 2009
[29] J. Hensel, G. Wang, Y. Li and J. Z. Zhang, “Synergistic effect of CdSe quantum dot sensitization and nitrogen doping of TiO2 nanostructures for photoelectrochemical solar hydrogen generation”, Nano Lett, Vol. 10, pp. 478-483, 2010
[30] 鄒年奎(洪哲文指導), “第一原理計算量子點光電性質提升光電化學太陽電池效能研究”, 清華大學動力機械系碩士論文, 2010.
[31] Japan Agency for Marine-Earth Science and Technology Kyoto University, “Global distribution of chlorophyll d widespread photosynthetic production using near-infrared light”, 2008
[32] Z. Liu, “Theoretical studies of natural pigments relevant to dye-sensitized solar cells”, Journal of Molecular Structure: Theochem, Vol. 862, pp. 44-48, 2008
[33] S. Meng, J. Ren and E. Kaxiras, “Natural dyes adsorbed on TiO2 nanowire for photovoltaic applications: enhanced light absorption and ultrafast electron injection”, Nano Lett, Vol. 8, pp. 3266-3272, 2008
[34] http://www.ag-chemieschulen.de/projektarbeit-naturstoffe-indikatoren.html
[35] P. M. Sirimanne, M. K. I. Senevirathna, E. V. A. Premalal, P. K. D. D. P. Pitigala, V. Sivakumar and K.Tennakone, “Utilization of natural pigment extracted from pomegranate fruits as sensitizer in solid-state solar cells”, Journal of Photochemistry and Photobiology A: Chemistry,Vol. 177, pp. 324-327, 2006
[36] 蔡岳璁(洪哲文指導), “ 計算量子力學於CO在直接甲醇燃料電池觸媒之毒化研究”, 清華大學動力機械系碩士論文, 2006