本論文主要探討有機五環素摻混富勒烯C60元件之光電流磁電導效應。磁電導效應與激發態濃度有相對關係，因此藉由改變摻混富勒烯C60的濃度、變換陰極功函數、施外加偏壓來控制元件中激發態的濃度高低，並利用元件結構的不同來討論分子間電場方向，來分析激發態濃度會影響到磁電導效應大小。另外在外加電場的作用下同時也發現磁電導效應圖形會有寬窄的改變，推測是電場大小影響了電荷轉移複合態(CT Complex)的電子電洞之距離，導致電荷轉移複合態的交換偶合作用力不同，因此磁電導效應會有變寬窄的變化。針對此磁電導寬窄的改變，我們試著用經驗公式來說明磁電導寬窄的變化。由上述結果中，我們認為激發態的濃度與距離是影響磁電導效應的關鍵，因此提出理論機制並驗證。

We investigate the magnetoconductances (MC) under illuminaion in pentacene blend fullerene C60 organic diodes. The MC is correlated to the concentration of the excited states. We control the concentration of excited state by blending C60 into pentacene, changing cathode material, applying bias voltage, and using double layers structure. By applying bias voltage, the negative MC is increased, and positive MC substantially broadens. We suggest that the broadened positive MC response depends on the e-h distance of charge transfer complex (CT Complex). To analysis the width of the MC curves , we ues an empirical formula to fit the MC curves at various bias volatges. As results, we show that, in addition to the concentration of excited states, the distance of excited state is also dominate during the formation of the MC.

[1]C. K. Chiang, C. R. Fincher, Jr., Y. W. Park, A. J.Heeger,H. Shirakawa, E. J. Louis, S. C. Gau, and A. G. Macdiarmid,“Electrical conductivity in doped polyacetylene,” Phys.Rev. Lett. 39, 1098 (1977).
[2]A. Köhler, J. S. Wilson, and R. H. Friend, “Fluorescence and phosphorescence in organic materials,” Adv. Mater. 14,701 (2002).
[3]R. H. Friend, R. W. Gymer, A. B. Holmes, J. H. Burroughes, R. N. Marks, C. Taliani, D. D. C. Bradley, D. A. Dos Santos, J. L. Brédas, M. Lögdlund, and W. R. Salaneck, “Electroluminescence in conjugated polymers,” Nature 397, 121 (1999).
[4]M. Lenes, G. J. A. H. Wetzelaer, F. B. Kooistra, S. C. Veenstra, K. J. Hummelen, and P. W. M. Blom, “Fullerene bisadducts for enhanced open-circuit voltages and efficiencies in polymer solar cells,” Adv. Mater. 20, 2116 (2008).
[5]D. Mühlbacher, M. Scharber, M. Morana, Z. Zhu, D. Waller, R. Gaudiana, and C. Brabec, “High photovoltaic performance of a low-bandgap polymer,” Adv. Mater. 18, 2884 (2006).
[6]D. Braga, and G. Horowitz, “Hige-performance organic field-effect transistors,” Adv. Mater. 21, 1473 (2009).
[7]J. Cornil, J. L. Brédas, J. Zaumseil, and H. Sirringhaus, “Ambipolar transport in organic conjugated materials,” Adv. Mater. 19, 1791 (2007).
[8]M. Pope, and C. E. Swenberg, “Electronic processes in organic crystals,” 2nd edition, Oxford university press, ISBN 978-0-19-512963-2 (1999).
[9]U. E. Steiner, and T. Ulrich, “Magnetic field effects in chemical kinetics and related phenomena,” Chem. Rev. 89, 51 (1989).
[10]R. E. Merrifield, “Theory of magnetic field effects on the mutual annihilation of triplet excitons,” J. Chem. Phys. 48, 4318 (1968).
[11]V. Ern, and R. E. Merrifield, “Magnetic field effect on triplet exciton quenching in organic crystals,” Phys. Rev. Lett. 21, 609 (1968).
[12]R. P. Groff, R. E. Merrifield, A. Suna, and P. Avakian, “Magnetic hyperfine modulation of dye-sensitized delayed fluorescence in an organic crystal,” Phys. Rev. Lett. 29, 823 (1972).
[13]E. L. Frankevich, A. A. Lymarev, I. Sokolik, F. E. Karasz, S. Blumstengel, and H. H. Horhold, “Polaron-pair generation in poly(phenylene vinylenes),” Phys. Rev. B 46, 9320 (1992).
[14]E. L. Frankevich, “On mechanisms of population of spin substates of polaron pairs,” Chem. Phys. 297, 315 (2004).
[15]V. Dyakonov, and E. L. Frankevich, “On the role played by polaron pairs in photophysical processes in semiconducting polymers,” Chem. Phys. 227, 203 (1998).
[16]J. Kalinowski, J. Szmytkowski, and W. Stampor, “Magnetic hyperfine modulation of charge photogeneration in solid films of Alq3,” Chem. Phys. Lett. 378, 380 (2003).
[17]J. Kalinowski, M. Cocchi, D. Virgili, P. D. Marco, and V. Fattori, “Magnetic field effects on emission and current in Alq3-based electroluminescent diodes,” Chem. Phys. Lett. 380, 710 (2003).
[18]Ö. Mermer, G. Veeraraghavan, T. L. Francis, Y. Sheng, D. T. Nguyen, M. Wohlgenannt, A. Köhler, M. K. Al-Suti, and M. S. Khan, “Large magnetoresistance in nonmagnetic π–conjugated semiconductor thin film devices,” Phys. Rev. B 72, 205202 (2005).
[19]B. Hu, and Y. Wu, “Tuning magnetoresistance between positive and negative values in organic semiconductors,” Nature Mater. 6,985 (2007).
[20]M. Wohlgenannt, and Z. V. Vardeny, “Spin-dependent exction formation rates in π–conjugated materials,” J. Phys. Condens. Matter 15, R83 (2003).
[21]I. V. Tolstov, A. V. Belov, M. G. Kaplunov, I. K. Yakuschenko, N. G. Spitsina, M. M. Triebel, and E. L. Frankevich, “On the role of magnetic field spin effect in photoconductivity of composite films of MEH-PPV and nanosized particles of PbS,” J. Lumin. 112, 368 (2005).
[22]N. J. Rolfe, M. Heeney, P. B. Wyatt, A. J. Drew, T. Kreouzis, and W. P. Gillin, “Elucidating the role of hyperfine interactions on organic magnetoresistance using deuterated aluminium tris(8-hydroxyquinoline),” Phys. Rev. B 80, 241201R (2009).
[23]P. Desai, P. Shakya, T. Kreouzis, and W. P. Gillin, “Magnetoresistance in organic light-emitting diode structures under illumination,” Phys. Rev. B 76, 235202 (2007).
[24]P. A. Bobbert, T. D. Nguyen, F. W. A. van Oost, B. Koopmans, and M.Wohlgenannt, “Bipolaron mechanism for organic magnetoresistance,” Phys. Rev. Lett. 99, 216801 (2007).
[25]P. Chen, Q. Peng, L. Yao, N. Gao, and F. Li, “Identifying the efficient inter-conversion between singlet and triplet charge-transfer states by magneto- electroluminescence study,” Appl. Phys. Lett. 102, 063301 (2013).
[26]F. J. Wang, H. Bässler, and Z. V. Vardeny, “Magnetic field effects in π–conjugated polymer-fullerene blends: Evidence for multiple components,” Phys. Rev. Lett. 101, 236805 (2008).
[27]W. S. Huang, T. H. Lee, T. F. Guo, J. C. A. Huang, and T. C. Wen, “Identifying the magnetoconductance responses by the induced charge transfer complex states in pentacene-based diodes,” Appl. Phys. Lett. 101, 053307 (2012).
[28]R. Eisberg, and R. Resnick, “Quantum physics of atoms, molecules, solids, nuclei, and particles”, 2nd edition, Wiley press, ISBN 0-471-87373-X (1985)
[29]W. Holzer, A. Penzkofer, and T. Tsuboi, “Absorption and emission spectroscopic characterization of Ir(ppy)3,” Chem. Phys. 308, 93 (2005).
[30]Y. Wu, and B. Hu, “Metal electrode effects on spin-orbital coupling and magnetoresistance in organic semiconductor devices,” Appl. Phys. Lett. 89, 203510 (2006).
[31]A. P. Monkman, H. D. Burrows, L. J. Hartwell, L. E. Horsburgh, I. Hamblett, and S. Navaratnam, “Triplet energies of π–conjugated polymers,” Phys. Rev. Lett. 86, 1358 (2001).
[32]A. Köhler, and D. Beljonne, “The singlet-triplet exchange energy in conjugated polymers,” Adv. Funct. Mater. 14, 11 (2004).
[33]A. Kadashchuk, A. Vakhnin, I. Blonski, D. Beljonne, Z. Shuai, J. L. Brédas, V. I. Arkhipov, P. Heremans, E. V. Emelianova, and H. Bässler, “Singlet-triplet splitting of geminate electron-hole pairs in conjugated polymers,” Phys. Rev. Lett. 93, 066803 (2004).
[34]M. A. Baldo, S. Lamansky, P. E. Burrows, M. E. Thompson, and S. R. Forrest, “Very high-efficiency green organic light-emitting devices based on electro- phosphorescence,” Appl. Phys. Lett. 75, 4 (1999).
[35]M. A. Baldo, and S. R. Forrest, “Transient analysis of organic electro- phosphorescence: I. Transient analysis of triplet energy transfer,” Phys. Rev. B 62, 10958 (2000).
[36]H. Ohkita, S. Cook, Y. Astuti, W. Duffy, S. Tierney, W. Zhang, M. Heeney, I. McCulloch, J. Nelson, D. D. C. Bradley, and J. R. Durrant, “Charge carrier formation in polythiophene/fullerene blend films studied by transient absorption spectroscopy,” J. Am. Chem. Soc. 130, 3030 (2008).
[37]M. Segal, M. A. Baldo, R. J. Holmes, S. R. Forrest, and Z. G. Soos, “Excitonic singlet-triplet ratios in molecular and polymeric organic materials,” Phys. Rev. B 68, 075211 (2003).
[38]B. Hu, L. Yan, and M. Shao, ”Magnetic-field effects in organic semiconducting materials and devices,” Adv. Mater. 21, 1500 (2009).
[39]J. Huang, and Y. Yang, “Origin of photomultiplication in C60 based devices,” Appl. Phys. Lett. 91, 203505 (2007).
[40]P. Shakya, P. Desai, T. Kreouzis, W. P. Gillin, S. M. Tuladhar, A. M. Ballantyne, and J. Nelson, “The effect of applied magnetic field on photocurrent generation in poly-3-hexylthiophene:[6,6]-phenyl C61-butyric acid methyl ester photovoltaic devices,” J. Phys.: Condens. Matter 20, 452203 (2008).
[41]Z. Xu, and B. Hu, “Photovoltaic processes of singlet and triplet excited states in organic solar cells,” Adv. Funct. Mater. 18, 2611 (2008).
[42]L. Yan, Y. Wu, Z. Xu, and B. Hu, “Positive and negative magnetic field effects in organic semiconducting materials,” Synth. Met. 159, 2323 (2009).
[43]M. Shao, L. Yan, M. Li, I. Ilia, and B. Hu, “Triplet-charge annihilation versus triplet-triplet annihilation in organic semiconductors,” J. Mater. Chem. C 1, 1330 (2013).
[44]H. Zang, Z. Xu, and B. Hu, “Magneto-optical investigations on the formation and dissociation of intermolecular charge-transfer complexes at donor-acceptor interfaces in bulk-heterojunction organic solar cells,” J. Phys. Chem. B 114, 5704 (2010).
[45]H. Zang, I. N. Ivanov, and B. Hu, “Magnetic studies of photovoltaic processes in organic solar cells,” IEEE J. Sel. Top. Quantum Electron. 16, 1801 (2010).
[46]T. H Lee, B. Hu, C. L. Tsai, R. S. Guan, T. C. Wen, T. F. Guo, and J. C. A. Huang, “The magneto conductance responses in polymer photovoltaic devices,” Org. Electron. 11, 677 (2010).