本研究探討有主動層材料pentacene成長在具微米溝槽結構之電洞傳輸層PEDOT:PSS 薄膜上之異質結構有機太陽能電池元件電特性，選用的p型材料為pentacene，n 型材料為PTCDI-C5H11，其目的是增加可見光區的吸收與p-n的界面，此種結構將有助於提升其光電轉換效率。利用原子力顯微鏡(AFM)觀察pentacene 分子和pentacene / PTCDI-C5H11分子成長在未壓印處理與壓印處理之PEDOT:PSS 薄膜上之表面型態差異性，證實對PEDOT:PSS 薄膜進行壓印處理能夠增加主動層之間接觸面積。最後，使用偏振吸收光譜討論pentacene 薄膜之吸收強度，比較出pentacene 分子成長在壓印處理與未壓印處理兩種不同PEDOT:PSS 薄膜上其薄膜結構上的差異性，未壓印元件之開路電壓Voc、短路電流Jsc、填充因子F.F.與轉換效率η分別為0.334 V、-3.250 mA/cm2、0.441與0.480 %，壓印元件之開路電壓Voc、短路電流Jsc、填充因子F.F.與轉換效率η分別為0.352 V、-9.5 mA/cm2、0.350與1.167 %；以具壓印及未壓印之PEDOT:PSS兩者相互觀察比較，光電轉換效率可提升3倍。其Jsc值9.5 mA/cm2是目前同款元件中比已發表論文最高值8.5 mA/cm2還高，明確的顯示壓印處理的微米溝槽可有效的提升其效率。

We studied the bi-layer structure organic solar cells (pentacene is donor ,and PTCDI-C5H11 is acceptor ).Pentacene film was deposited on a hole transport layer PEDOT:PSS with periodic micro grove structure.

Based on this structure, we obtained about three times of energy conversion efficiency η= 1.16 % compare to a planar bi-layer structure η=0.35 %.This effect is due to the increase of interface area of pentacene/PEDOT:PSS and pentacene/ PTCDI-C5H11 that can help the hole transportation and exciton separation respectively. The short circuit current Jsc ~9.5 mA/cm2 ,we obtained is higher than other published data (Jsc=8.5 mA/cm2).We also applied UV-visible absorption spectrum , X-Ray diffraction , atomic force microscopy to investigate the organic films and solar cell devices.

[1]. C. W. Tang, ”Two-layer organic photovoltaic cell”, Appl. Phys. Lett.
48.83(1986).

[2].P. Peumans, V. Bulovi, S. R. Forrest. , ” Efficient photon harvesting at high optical intensities in ultrathin organic double-heterostructure photovoltaic diodes”, Appl. Phys. Lett. 76, 2650 (2000).
[3].P. Peumans ,S. R. Forrest. ,” Very-high-efficiency double hetero-
structure copper phthalocyanine/C60 photovoltaic cells”, Appl. Phys.
Lett. 79, 126 (2001).

[4]. J. Xue, S. Uchida, B. P. Rand, S. R. Forrest. ,” Asymmetric tandem organic photovoltaic cells with hybrid planar-mixed molecular hetero- junctions”, Appl. Phys. Lett. 85, 5757 (2004).

[5]. J. Xue, B. P. Rand, S. Uchida, and S. R. Forrest, Adv. Mater. (in press).

[6]. A. K. Pandey, S. Dabos-Seignon, and J.M. Nunzi ,” Pentacene: PTCDI -C13H27 molecular blends efficiently harvest light for solar cell applications”, Appl. Phys. Lett. 89, 113506 (2006).

[7]. S. Karak, V.S. Reddy, S.K. Ray, A. Dhar ,” Organic photovoltaic devices based on pentacene/N,N0-dioctyl-3,4,9,10-perylenedicarboxi- mide heterojunctions” ,Org. Electron. 10 1006–1010 (2009)

[8].N. S. Sariciftci, L. Smilowitz, A. J. Heeger, F. Wudi ,” Photoinduced Electron Transfer from a Conducting Polymer to Buckminster fullere- ene ”, Science 258 ,1474 (1992).

[9]. J. C. Hummelen, B. W. Knight, F. LePeq, and F.Wudi ,” Preparation and Characterization of Fulleroid and Methanofullerene Derivatives”, J. Org. Chem.60, 532-538(1995).

[10].G. Yu, J. Gao, J. C. Hummelen, F. Wudi, A. J. Heeger ,” Polymer Photovoltaic Cells: Enhanced Efficiencies via a Network of Internal Donor-Acceptor Heterojunctions”, Science 270 ,1789 (1995).

[11]. S.E. Shaheen, C. J. Brabec, N. S.Sariciftci, F. Padinger ,T. Fromherz, J. C. Hummelen ,” 2.5% efficient organic plastic solar cells” , Appl. Phys. Lett. 78, 841 (2001).

[12] G. E. Jabbour, B. Kippelen, N. R. Armstrong, and N. Peyghambarian, “Aluminum based cathode structure for enhanced electron injection in electroluminescent organic devices ”Appl. Phys. Lett. 73, 1185 (1998)

[13] L. S. Hung, C. W. Tang, and M. G. Mason, “Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode” , Appl. Phys. Lett. 70, 152 (1997)

[14] .F. Padinger , R. S. Rittberger, N. S. Sariciftci ,”Effect of post-
production treatment on plastic solar cells ”, Adv.funct.Mater. 13, 85
(2003).

[15].W. Ma, C .Yang , X .Gong , K . Lee , A .J .Heeger. ,”Thermally
stable, efficient polymer solar cells with nanoscale control of the
interpenetrating network morphology”, Adv.funct.Mater. 15,1617
(2003).

[16]. J. Y. Kim, K. Lee, N. E. Coates, D. Moses, T.Q. Nguyen, M. Dante, A. J. Heeger. ,” Efficient tandem polymer solar cells fabricated by all-solution processing”, Science 317 ,222-225 (1995).

[17]. S. H. Park, A. Roy, S. Beaupre, S. Cho, N. Coates, J. S. Moon,
D. Moses, M. Leclerc, K. Lee , A. J. Heeger. ,” Bulk heterojunction solar cells with internal quantum efficiency approaching 100%”, Nature Photon., 3,297-302 (2009).

[18]. H. Y. Chen, J. Hou, S. Zhang, Y. Liang, G. Yang, Y. Yang, L. Yu, Y. Wu , G. Li, ” Polymer solar cells with enhanced open-circuit voltage and efficiency”, Nature Photon.3,649-653(2009).
[19]. Henry. J. H. Chen , M.T. Huang, Y.B. Liu,” Fabrication of Au/PEDOT stacked electrodes for organic thin film transistors by imprinting technology”, Microelectron. Reliability ,50 717–721 (2010)

[20] C. F. Shih,_ K. T. Hung, J. W. Wu, C. Y. Hsiao, W. M. Li,
” Efficiency improvement of blended poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6) C61 solar cells by nanoimprinting ” , Appl. Phys. Lett. 94, 143505 (2009).

[21] J. H. Lee, D. W. Kim, H. Jang, J. K. Choi, J. Geng, J. W. Jung,
S. C. Yoon, H.T. Jung ,” Enhanced solar cell efficiency in bulk heterojunction polymer systems obtained by nanoimprinting with
commercially available AAO membrane filters”, small 19,2139-
2143 (2009)

[22]. M.G. Kang, M. S. Kim, J. Kim, and L. J. Guo.” Organic solar cells using nanoimprinted transparent metal electrodes”, Adv.Mater. 20,4408-4413 (2008).

[23]. A. Moliton , J.M. Nunzi,” How to model the behaviour of organic photovoltaic cells” Polym. Int. 55, 583 (2006).

[24]. I.P.M. Bouchoms, W.A. Schoonveld, J. Vrijmoeth, T.M. Klapwijk,
“Solvent-induced phase transition in thermally evaporated pentacene films”Appl. Phys. Lett. 74 3302 (1999).

[25]. W.A. Schoonveld, Ph.D. Thesis, RuG, (1999).

[26]. C. C. Mattheus, G. A. de Wijs, R. A. de Groot ,T. T.M.Palstra,
“Modeling the Polymorphism of Pentacene”, J. Am. Chem. Soc.,
125,6323 (2003).

[27]. I. P. M. Bouchoms, W. A. Schoonveld, Vrijmoeth, J. T.M.Klapwijk,
“Morphology identification of the thin film phases of vacuum
evaporated pentacene on SiO2 substrates”, Synth.Met.,104,175
(1999).

[28].T. Jentzsch, H. J. Juepner, K.-W. Brzezinka and A. Lau,"efficiency of optical second harmonic generation from pentacene films of different morphology and structure”, Thin Solid Films, 315, 273 (1998).

[29].C. C. Mattheus, A. B. Dros, J. Baas, G. T. Oostergetel,A. Meetsma,
J. L. de Boer, T. T.M. Palstra,"Identification of polymorphs of pentacene". Synth. Met. 138 (2003).

[30]. D. Faltermeier, B. Gompf, M. Dressel, A. K. Tripathi, J. Pflaum,
” Optical properties of pentacene thin films and single crystals”
Phys. Rev. B 74, 125416 (2006).

[31]. J.A. Last, A.C. Hillier,D. E. Hooks, J. B. Maxson, M. D. Ward ,”
Epitaxially Driven Assembly of Crystalline Molecular Films on
Ordered Substrates” Chem. Mater. 10, 422-437 (1998).