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Annual Review of Physical Chemistry

Volume 65, 2014

Phase Separation in Bulk Heterojunctions of Semiconducting Polymers and Fullerenes for Photovoltaics

Abstract

Thin-film solar cells are an important source of renewable energy. The most efficient thin-film solar cells made with organic materials are blends of semiconducting polymers and fullerenes called the bulk heterojunction (BHJ). Efficient BHJs have a nanoscale phase-separated morphology that is formed during solution casting. This article reviews recent work to understand the nature of the phase-separation process resulting in the formation of the domains in polymer-fullerene BHJs. The BHJ is now viewed as a mixture of polymer-rich, fullerene-rich, and mixed polymer-fullerene domains. The formation of this structure can be understood through fundamental knowledge of polymer physics. The implications of this structure for charge transport and charge generation are given.

Keyword(s): organic electronics
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2014-04-01
2024-04-19
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Literature Cited

  1. Ginley D, Green MA, Collins R. 1.  2008. Solar energy conversion toward 1 terawatt. MRS Bull. 33:355–64 [Google Scholar]
  2. Chu S, Majumdar A. 2.  2012. Opportunities and challenges for a sustainable energy future. Nature 488:294–303 [Google Scholar]
  3. Shah A, Torres P, Tscharner R, Wyrsch N, Keppner H. 3.  1999. Photovoltaic technology: the case for thin-film solar cells. Science 285:692–98 [Google Scholar]
  4. Thompson BC, Fréchet JMJ. 4.  2008. Polymer-fullerene composite solar cells. Angew. Chem. Int. Ed. Engl. 47:58–77 [Google Scholar]
  5. Sun Y, Welch GC, Leong WL, Takacs CJ, Bazan GC, Heeger AJ. 5.  2012. Solution-processed small-molecule solar cells with 6.7% efficiency. Nat. Mater. 11:44–48 [Google Scholar]
  6. Chen G, Sasabe H, Wang Z, Wang X-F, Hong Z. 6.  et al. 2012. Co-evaporated bulk heterojunction solar cells with >6.0% efficiency. Adv. Mater. 24:2768–73 [Google Scholar]
  7. You J, Dou L, Yoshimura K, Kato T, Ohya K. 7.  et al. 2013. A polymer tandem solar cell with 10.6% power conversion efficiency. Nat. Commun. 4:1446 [Google Scholar]
  8. Yang XN, Loos J, Veenstra SC, Verhees WJH, Wienk MM. 8.  et al. 2005. Nanoscale morphology of high-performance polymer solar cells. Nano Lett. 5:579–83 [Google Scholar]
  9. Janssen RAJ, Nelson J. 9.  2013. Factors limiting device efficiency in organic photovoltaics. Adv. Mater. 25:1847–58 [Google Scholar]
  10. Brédas J-L, Norton JE, Cornil J, Coropceanu V. 10.  2009. Molecular understanding of organic solar cells: the challenges. Acc. Chem. Res. 42:1691–99 [Google Scholar]
  11. Sumpter BG, Meunier V. 11.  2012. Can computational approaches aid in untangling the inherent complexity of practical organic photovoltaic systems?. J. Polym. Sci. B 50:1071–89 [Google Scholar]
  12. Treat ND, Mates TE, Hawker CJ, Kramer EJ, Chabinyc ML. 12.  2013. Temperature dependence of the diffusion coefficient of PCBM in poly(3-hexylthiophene). Macromolecules 46:1002–7 [Google Scholar]
  13. Treat ND, Varotto A, Takacs CJ, Batara N, Al-Hashimi M. 13.  et al. 2012. Polymer-fullerene miscibility: a metric for screening new materials for high-performance organic solar cells. J. Am. Chem. Soc. 134:15869–79 [Google Scholar]
  14. Treat ND, Brady MA, Smith G, Toney MF, Kramer EJ. 14.  et al. 2011. Interdiffusion of PCBM and P3HT reveals miscibility in a photovoltaically active blend. Adv. Energy Mater. 1:82–89 [Google Scholar]
  15. Collins BA, Li Z, Tumbleston JR, Gann E, McNeill CR, Ade H. 15.  2013. Absolute measurement of domain composition and nanoscale size distribution explains performance in PTB7:PC71BM solar cells. Adv. Energy Mater. 3:65–74 [Google Scholar]
  16. Collins BA, Li Z, McNeill CR, Ade H. 16.  2011. Fullerene-dependent miscibility in the silole-containing copolymer PSBTBT-08. Macromolecules 44:9747–51 [Google Scholar]
  17. Collins BA, Gann E, Guignard L, He X, McNeill CR, Ade H. 17.  2010. Molecular miscibility of polymer-fullerene blends. J. Phys. Chem. Lett. 1:3160–66 [Google Scholar]
  18. Watts B, Belcher WJ, Thomsen L, Ade H, Dastoor PC. 18.  2009. A quantitative study of PCBM diffusion during annealing of P3HT:PCBM blend films. Macromolecules 42:8392–97 [Google Scholar]
  19. Yin W, Dadmun M. 19.  2011. A new model for the morphology of P3HT/PCBM organic photovoltaics from small-angle neutron scattering: rivers and streams. ACS Nano 5:4756–68 [Google Scholar]
  20. Chen D, Nakahara A, Wei D, Nordlund D, Russell TP. 20.  2010. P3HT/PCBM bulk heterojunction organic photovoltaics: correlating efficiency and morphology. Nano Lett. 11:561–67 [Google Scholar]
  21. Zhou H, Yang L, You W. 21.  2012. Rational design of high performance conjugated polymers for organic solar cells. Macromolecules 45:607–32 [Google Scholar]
  22. Boudreault P-LT, Najari A, Leclerc M. 22.  2011. Processable low-bandgap polymers for photovoltaic applications. Chem. Mater. 23:456–69 [Google Scholar]
  23. Clarke TM, Durrant JR. 23.  2010. Charge photogeneration in organic solar cells. Chem. Rev. 110:6736–67 [Google Scholar]
  24. Piliego C, Loi MA. 24.  2012. Charge transfer state in highly efficient polymer-fullerene bulk heterojunction solar cells. J. Mater. Chem. 22:4141–50 [Google Scholar]
  25. Blom PWM, Mihailetchi VD, Koster LJA, Markov DE. 25.  2007. Device physics of polymer:fullerene bulk heterojunction solar cells. Adv. Mater. 19:1551–66 [Google Scholar]
  26. Donald AM, Windle AH, Hanna S. 26.  2006. Liquid Crystalline Polymers Cambridge, UK: Cambridge Univ. Press
  27. Heffner GW, Pearson DS. 27.  1991. Molecular characterization of poly(3-hexylthiophene). Macromolecules 24:6295–99 [Google Scholar]
  28. McCulloch B, Ho V, Hoarfrost M, Stanley C, Do C. 28.  et al. 2013. Polymer chain shape of poly(3-alkylthiophenes) in solution using small-angle neutron scattering. Macromolecules 46:1899–907 [Google Scholar]
  29. Westenhoff S, Beenken WJD, Yartsev A, Greenham NC. 29.  2006. Conformational disorder of conjugated polymers. J. Chem. Phys. 125:154903 [Google Scholar]
  30. Malik S, Jana T, Nandi AK. 30.  2001. Thermoreversible gelation of regioregular poly(3-hexylthiophene) in xylene. Macromolecules 34:275–82 [Google Scholar]
  31. Grell M, Bradley DDC, Inbasekaran M, Ungar G, Whitehead KS, Woo EP. 31.  2000. Intrachain ordered polyfluorene. Synth. Met. 111–112:579–81 [Google Scholar]
  32. Cotts PM, Swager TM, Zhou Q. 32.  1996. Equilibrium flexibility of a rigid linear conjugated polymer. Macromolecules 29:7323–28 [Google Scholar]
  33. Berry GC. 33.  1978. Properties of an optically anisotropic heterocyclic ladder polymer (BBL) in dilute solution. J. Polym. Sci. Polym. Symp. 65:143–72 [Google Scholar]
  34. Cheng SZD, Wunderlich B. 34.  1986. Molecular segregation and nucleation of poly(ethylene oxide) crystallized from the melt. 1. Calorimetric study. J. Polym. Sci. B 24:577–94 [Google Scholar]
  35. Koch FPV, Heeney M, Smith P. 35.  2013. Thermal and structural characteristics of oligo(3-hexylthiophene)s (3HT)n, n = 4–36. J. Am. Chem. Soc. 135:13699–709 [Google Scholar]
  36. Li G, Yao Y, Yang H, Shrotriya V, Yang G, Yang Y. 36.  2007. “Solvent annealing” effect in polymer solar cells based on poly(3-hexylthiophene) and methanofullerenes. Adv. Funct. Mater. 17:1636–44 [Google Scholar]
  37. Treat ND, Shuttle CG, Toney MF, Hawker CJ, Chabinyc ML. 37.  2011. In situ measurement of power conversion efficiency and molecular ordering during thermal annealing in P3HT:PCBM bulk heterojunction solar cells. J. Mater. Chem. 21:15224–31 [Google Scholar]
  38. Verploegen E, Mondal R, Bettinger CJ, Sok S, Toney MF, Bao ZA. 38.  2010. Effects of thermal annealing upon the morphology of polymer-fullerene blends. Adv. Funct. Mater. 20:3519–29 [Google Scholar]
  39. Mayer AC, Toney MF, Scully SR, Rivnay J, Brabec CJ. 39.  et al. 2009. Bimolecular crystals of fullerenes in conjugated polymers and the implications of molecular mixing for solar cells. Adv. Funct. Mater. 19:1173–79 [Google Scholar]
  40. Rivnay J, Mannsfeld SCB, Miller CE, Salleo A, Toney MF. 40.  2012. Quantitative determination of organic semiconductor microstructure from the molecular to device scale. Chem. Rev. 112:5488–519 [Google Scholar]
  41. Turnbull D, Fisher JC. 41.  1949. Rate of nucleation in condensed systems. J. Chem. Phys. 17:71–73 [Google Scholar]
  42. Wunderlich B. 42.  1976. Macromolecular Physics: Crystal Nucleation, Growth, Annealing San Diego: Academic
  43. Holland VF, Lindenmeyer PH. 43.  1962. Morphology and crystal growth rate of polyethylene crystalline complexes. J. Polym. Sci. 57:589–608 [Google Scholar]
  44. Koch FPV, Rivnay J, Foster S, Müller C, Downing JM. 44.  et al. 2013. The impact of molecular weight on microstructure and charge transport in semicrystalline polymer semiconductors: poly(3-hexylthiophene), a model study. Prog. Polym. Sci. 381978–89
  45. Brinkmann M, Rannou P. 45.  2009. Molecular weight dependence of chain packing and semicrystalline structure in oriented films of regioregular poly(3-hexylthiophene) revealed by high-resolution transmission electron microscopy. Macromolecules 42:1125–30 [Google Scholar]
  46. Takacs CJ, Treat ND, Krämer S, Chen Z, Facchetti A. 46.  et al. 2013. Remarkable order of a high-performance polymer. Nano Lett. 13:2522–27 [Google Scholar]
  47. Mena-Osteritz E, Meyer A, Langeveld-Voss BMW, Janssen RAJ, Meijer EW, Bäuerle P. 47.  2000. Two-dimensional crystals of poly(3-alkyl-thiophene)s: direct visualization of polymer folds in submolecular resolution. Angew. Chem. Int. Ed. Engl. 39:2679–84 [Google Scholar]
  48. Keg P, Lohani A, Fichou D, Lam YM, Wu Y. 48.  et al. 2008. Direct observation of alkyl chain interdigitation in conjugated polyquarterthiophene self-organized on graphite surfaces. Macromol. Rapid Commun. 29:1197–202 [Google Scholar]
  49. Liu J, Arif M, Zou J, Khondaker SI, Zhai L. 49.  2009. Controlling poly(3-hexylthiophene) crystal dimension: nanowhiskers and nanoribbons. Macromolecules 42:9390–93 [Google Scholar]
  50. Zhang R, Li B, Iovu MC, Jeffries-EL M, Sauve G. 50.  et al. 2006. Nanostructure dependence of field-effect mobility in regioregular poly(3-hexylthiophene) thin film field effect transistors. J. Am. Chem. Soc. 128:3480–81 [Google Scholar]
  51. Brun M, Demadrille R, Rannou P, Pron A, Travers JP, Grevin B. 51.  2004. Multiscale scanning tunneling microscopy study of self-assembly phenomena in two-dimensional polycrystals of π-conjugated polymers: the case of regioregular poly(dioctylbithiophene-alt-fluorenone). Adv. Mater. 16:2087–92 [Google Scholar]
  52. Poisson SD, Schnuse CH. 52.  1841. Recherches sur la probabilité des jugements en matière criminelle et en matière civile Paris: Meyer
  53. Avrami M. 53.  1941. Granulation, phase change, and microstructure kinetics of phase change. III. J. Chem. Phys. 9:177–84 [Google Scholar]
  54. Avrami M. 54.  1940. Kinetics of phase change. II Transformation-time relations for random distribution of nuclei. J. Chem. Phys. 8:212–24 [Google Scholar]
  55. Avrami M. 55.  1939. Kinetics of phase change. I General theory. J. Chem. Phys. 7:1103–12 [Google Scholar]
  56. Malik S, Nandi AK. 56.  2002. Crystallization mechanism of regioregular poly(3-alkyl thiophene)s. J. Polym. Sci. B 40:2073–85 [Google Scholar]
  57. Kiriy N, Jahne E, Adler HJ, Schneider M, Kiriy A. 57.  et al. 2003. One-dimensional aggregation of regioregular polyalkylthiophenes. Nano Lett. 3:707–12 [Google Scholar]
  58. Ihn KJ, Moulton J, Smith P. 58.  1993. Whiskers of poly(3-alkylthiophene)s. J. Polym. Sci. B 31:735–42 [Google Scholar]
  59. Rahimi K, Botiz I, Stingelin N, Kayunkid N, Sommer M. 59.  et al. 2012. Controllable processes for generating large single crystals of poly(3-hexylthiophene). Angew. Chem. Int. Ed. Engl. 51:11131–35 [Google Scholar]
  60. O'Carroll D, Iacopino D, O'Riordan A, Lovera P, O'Connor E. 60.  et al. 2008. Poly(9,9-dioctylfluorene) nanowires with pronounced β-phase morphology: synthesis, characterization, and optical properties. Adv. Mater. 20:42–48 [Google Scholar]
  61. Briseno AL, Mannsfeld SCB, Shamberger PJ, Ohuchi FS, Bao Z. 61.  et al. 2008. Self-assembly, molecular packing, and electron transport in n-type polymer semiconductor nanobelts. Chem. Mater. 20:4712–19 [Google Scholar]
  62. Li W, Hendriks KH, Roelofs WSC, Kim Y, Wienk MM, Janssen RAJ. 62.  2013. Efficient small bandgap polymer solar cells with high fill factors for 300 nm thick films. Adv. Mater. 25:3182–86 [Google Scholar]
  63. Moon JS, Takacs CJ, Cho S, Coffin RC, Kim H. 63.  et al. 2010. Effect of processing additive on the nanomorphology of a bulk heterojunction material. Nano Lett. 10:4005–8 [Google Scholar]
  64. Kozub DR, Vakhshouri K, Orme LM, Wang C, Hexemer A, Gomez ED. 64.  2011. Polymer crystallization of partially miscible polythiophene/fullerene mixtures controls morphology. Macromolecules 44:5722–26 [Google Scholar]
  65. Cheung DL, Troisi A. 65.  2010. Theoretical study of the organic photovoltaic electron acceptor PCBM: morphology, electronic structure, and charge localization. J. Phys. Chem. C 114:20479–88 [Google Scholar]
  66. Tummala NR, Mehraeen S, Fu Y-T, Risko C, Brédas J-L. 66.  2013. Materials-scale implications of solvent and temperature on [6,6]-phenyl-C61-butyric acid methyl ester (PCBM): a theoretical perspective. Adv. Funct. Mater. 235800–13
  67. Savenije TJ, Kroeze JE, Yang XN, Loos J. 67.  2005. The effect of thermal treatment on the morphology and charge carrier dynamics in a polythiophene-fullerene bulk heterojunction. Adv. Funct. Mater. 15:1260–66 [Google Scholar]
  68. Bertho S, Janssen G, Cleij TJ, Conings B, Moons W. 68.  et al. 2008. Effect of temperature on the morphological and photovoltaic stability of bulk heterojunction polymer:fullerene solar cells. Sol. Energy Mater. Sol. Cells 92:753–60 [Google Scholar]
  69. Li L, Lu G, Li S, Tang H, Yang X. 69.  2008. Epitaxy-assisted creation of PCBM nanocrystals and its application in constructing optimized morphology for bulk-heterojunction polymer solar cells. J. Phys. Chem. B 112:15651–58 [Google Scholar]
  70. Yang XN, Alexeev A, Michels MAJ, Loos J. 70.  2005. Effect of spatial confinement on the morphology evolution of thin poly(p-phenylenevinylene)/methanofullerene composite films. Macromolecules 38:4289–95 [Google Scholar]
  71. Rispens MT, Meetsma A, Rittberger R, Brabec CJ, Sariciftci NS, Hummelen JC. 71.  2003. Influence of the solvent on the crystal structure of PCBM and the efficiency of MDMO-PPV: PCBM ‘plastic’ solar cells. Chem. Commun. 2003:2116–18 [Google Scholar]
  72. Casalegno M, Zanardi S, Frigerio F, Po R, Carbonera C. 72.  et al. 2013. Solvent-free phenyl-C61-butyric acid methyl ester (PCBM) from clathrates: insights for organic photovoltaics from crystal structures and molecular dynamics. Chem. Commun. 49:4525–27 [Google Scholar]
  73. Treat ND, Nekuda Malik JA, Reid O, Yu L, Shuttle CG. 73.  et al. 2013. Microstructure formation in molecular and polymer semiconductors assisted by nucleation agents. Nat. Mater. 12:628–33 [Google Scholar]
  74. Lindqvist C, Sanz-Velasco A, Wang E, Backe O, Gustafsson S. 74.  et al. 2013. Nucleation-limited fullerene crystallisation in a polymer-fullerene bulk-heterojunction blend. J. Mater. Chem. A 1:7174–80 [Google Scholar]
  75. Chang L, Lademann HWA, Bonekamp J-B, Meerholz K, Moule AJ. 75.  2011. Effect of trace solvent on the morphology of P3HT:PCBM bulk heterojunction solar cells. Adv. Funct. Mater. 21:1779–87 [Google Scholar]
  76. Hoppe H, Niggemann M, Winder C, Kraut J, Hiesgen R. 76.  et al. 2004. Nanoscale morphology of conjugated polymer/fullerene-based bulk-heterojunction solar cells. Adv. Funct. Mater. 14:1005–11 [Google Scholar]
  77. He C, Germack DS, Kline RJ, Delongchamp DM, Fischer DA. 77.  et al. 2011. Influence of substrate on crystallization in polythiophene/fullerene blends. Sol. Energy Mater. Sol. Cells 95:1375–81 [Google Scholar]
  78. Wu W-R, Jeng US, Su C-J, Wei K-H, Su M-S. 78.  et al. 2011. Competition between fullerene aggregation and poly(3-hexylthiophene) crystallization upon annealing of bulk heterojunction solar cells. ACS Nano 5:6233–43 [Google Scholar]
  79. Li Z, Wong HC, Huang Z, Zhong H, Tan CH. 79.  et al. 2013. Performance enhancement of fullerene-based solar cells by light processing. Nat. Commun. 4:2227 [Google Scholar]
  80. He X, Collins BA, Watts B, Ade H, McNeill CR. 80.  2012. Studying polymer/fullerene intermixing and miscibility in laterally patterned films with X-ray spectromicroscopy. Small 8:1920–27 [Google Scholar]
  81. Collins BA, Tumbleston JR, Ade H. 81.  2011. Miscibility, crystallinity, and phase development in P3HT/PCBM solar cells: toward an enlightened understanding of device morphology and stability. J. Phys. Chem. Lett. 2:3135–45 [Google Scholar]
  82. Chen D, Liu F, Wang C, Nakahara A, Russell TP. 82.  2011. Bulk heterojunction photovoltaic active layers via bilayer interdiffusion. Nano Lett. 11:2071–78 [Google Scholar]
  83. Chen D, Nakahara A, Wei D, Nordlund D, Russell TP. 83.  2011. P3HT/PCBM bulk heterojunction organic photovoltaics: correlating efficiency and morphology. Nano Lett. 11:561–67 [Google Scholar]
  84. Lilliu S, Agostinelli T, Pires E, Hampton M, Nelson J, Macdonald JE. 84.  2011. Dynamics of crystallization and disorder during annealing of P3HT/PCBM bulk heterojunctions. Macromolecules 44:2725–34 [Google Scholar]
  85. Lu H, Akgun B, Russell TP. 85.  2011. Morphological characterization of a low-bandgap crystalline polymer:PCBM bulk heterojunction solar cells. Adv. Energy Mater. 1:870–78 [Google Scholar]
  86. Chen H, Hegde R, Browning J, Dadmun MD. 86.  2012. The miscibility and depth profile of PCBM in P3HT: thermodynamic information to improve organic photovoltaics. Phys. Chem. Chem. Phys. 14:5635–41 [Google Scholar]
  87. Flory PJ. 87.  1953. Principles of Polymer Chemistry Ithaca, NY: Cornell Univ. Press
  88. Yiu AT, Beaujuge PM, Lee OP, Woo CH, Toney MF, Fréchet JMJ. 88.  2012. Side-chain tunability of furan-containing low-band-gap polymers provides control of structural order in efficient solar cells. J. Am. Chem. Soc. 134:2180–85 [Google Scholar]
  89. Troshin PA, Hoppe H, Renz J, Egginger M, Mayorova JY. 89.  et al. 2009. Material solubility-photovoltaic performance relationship in the design of novel fullerene derivatives for bulk heterojunction solar cells. Adv. Funct. Mater. 19:779–88 [Google Scholar]
  90. Müller C, Ferenczi TAM, Campoy-Quiles M, Frost JM, Bradley DDC. 90.  et al. 2008. Binary organic photovoltaic blends: a simple rationale for optimum compositions. Adv. Mater. 20:3510–15 [Google Scholar]
  91. Kouijzer S, Michels JJ, van den Berg M, Gevaerts VS, Turbiez M. 91.  et al. 2013. Predicting morphologies of solution processed polymer:fullerene blends. J. Am. Chem. Soc. 135:12057–67 [Google Scholar]
  92. Chou KW, Yan B, Li R, Li EQ, Zhao K. 92.  et al. 2013. Spin-cast bulk heterojunction solar cells: a dynamical investigation. Adv. Mater. 25:1923–29 [Google Scholar]
  93. Schmidt-Hansberg B, Klein MFG, Sanyal M, Buss F, de Medeiros GQG. 93.  et al. 2012. Structure formation in low-bandgap polymer:fullerene solar cell blends in the course of solvent evaporation. Macromolecules 45:7948–55 [Google Scholar]
  94. Schmidt-Hansberg B, Sanyal M, Klein MFG, Pfaff M, Schnabel N. 94.  et al. 2011. Moving through the phase diagram: morphology formation in solution cast polymer-fullerene blend films for organic solar cells. ACS Nano 5:8579–90 [Google Scholar]
  95. Erb T, Zhokhavets U, Gobsch G, Raleva S, Stuhn B. 95.  et al. 2005. Correlation between structural and optical properties of composite polymer/fullerene films for organic solar cells. Adv. Funct. Mater. 15:1193–96 [Google Scholar]
  96. Ma WL, Yang CY, Gong X, Lee K, Heeger AJ. 96.  2005. Thermally stable, efficient polymer solar cells with nanoscale control of the interpenetrating network morphology. Adv. Funct. Mater. 15:1617–22 [Google Scholar]
  97. Rogers JT, Schmidt K, Toney MF, Bazan GC, Kramer EJ. 97.  2012. Time-resolved structural evolution of additive-processed bulk heterojunction solar cells. J. Am. Chem. Soc. 134:2884–87 [Google Scholar]
  98. Li G, Shrotriya V, Huang JS, Yao Y, Moriarty T. 98.  et al. 2005. High-efficiency solution processable polymer photovoltaic cells by self-organization of polymer blends. Nat. Mater. 4:864–68 [Google Scholar]
  99. Kim Y, Cook S, Tuladhar SM, Choulis SA, Nelson J. 99.  et al. 2006. A strong regioregularity effect in self-organizing conjugated polymer films and high-efficiency polythiophene:fullerene solar cells. Nat. Mater. 5:197–203 [Google Scholar]
  100. Peet J, Kim JY, Coates NE, Ma WL, Moses D. 100.  et al. 2007. Efficiency enhancement in low-bandgap polymer solar cells by processing with alkane dithiols. Nat. Mater. 6:497–500 [Google Scholar]
  101. Peet J, Senatore ML, Heeger AJ, Bazan GC. 101.  2009. The role of processing in the fabrication and optimization of plastic solar cells. Adv. Mater. 21:1521–27 [Google Scholar]
  102. Vakhshouri K, Gomez ED. 102.  2012. Effect of crystallization kinetics on microstructure and charge transport of polythiophenes. Macromol. Rapid Commun. 33:2133–37 [Google Scholar]
  103. Zhao K, Khan HU, Li R, Su Y, Amassian A. 103.  2013. Entanglement of conjugated polymer chains influences molecular self-assembly and carrier transport. Adv. Funct. Mater. 236024–35
  104. Schilinsky P, Asawapirom U, Scherf U, Biele M, Brabec CJ. 104.  2005. Influence of the molecular weight of poly(3-hexylthiophene) on the performance of bulk heterojunction solar cells. Chem. Mater. 17:2175–80 [Google Scholar]
  105. Coffin RC, Peet J, Rogers J, Bazan GC. 105.  2009. Streamlined microwave-assisted preparation of narrow-bandgap conjugated polymers for high-performance bulk heterojunction solar cells. Nat. Chem. 1:657–61 [Google Scholar]
  106. Chu T-Y, Lu J, Beaupré S, Zhang Y, Pouliot J-R. 106.  et al. 2012. Effects of the molecular weight and the side-chain length on the photovoltaic performance of dithienosilole/thienopyrrolodione copolymers. Adv. Funct. Mater. 22:2345–51 [Google Scholar]
  107. Müller C, Wang E, Andersson LM, Tvingstedt K, Zhou Y. 107.  et al. 2010. Influence of molecular weight on the performance of organic solar cells based on a fluorene derivative. Adv. Funct. Mater. 20:2124–31 [Google Scholar]
  108. Tong M, Cho S, Rogers JT, Schmidt K, Hsu BBY. 108.  et al. 2010. Higher molecular weight leads to improved photoresponsivity, charge transport and interfacial ordering in a narrow bandgap semiconducting polymer. Adv. Funct. Mater. 20:3959–65 [Google Scholar]
  109. Gierschner J, Cornil J, Egelhaaf H-J. 109.  2007. Optical bandgaps of π-conjugated organic materials at the polymer limit: experiment and theory. Adv. Mater. 19:173–91 [Google Scholar]
  110. Guo J, Ohkita H, Benten H, Ito S. 110.  2010. Charge generation and recombination dynamics in poly(3-hexylthiophene)/fullerene blend films with different regioregularities and morphologies. J. Am. Chem. Soc. 132:6154–64 [Google Scholar]
  111. Jamieson FC, Domingo EB, McCarthy-Ward T, Heeney M, Stingelin N, Durrant JR. 111.  2012. Fullerene crystallisation as a key driver of charge separation in polymer/fullerene bulk heterojunction solar cells. Chem. Sci. 3:485–92 [Google Scholar]
  112. Street RA, Davies D, Khlyabich PP, Burkhart B, Thompson BC. 112.  2013. Origin of the tunable open-circuit voltage in ternary blend bulk heterojunction organic solar cells. J. Am. Chem. Soc. 135:986–89 [Google Scholar]
  113. Vandewal K, Tvingstedt K, Gadisa A, Inganas O, Manca JV. 113.  2010. Relating the open-circuit voltage to interface molecular properties of donor:acceptor bulk heterojunction solar cells. Phys. Rev. B 81:125204 [Google Scholar]
  114. Ma W, Tumbleston JR, Wang M, Gann E, Huang F, Ade H. 114.  2013. Domain purity, miscibility, and molecular orientation at donor/acceptor interfaces in high performance organic solar cells: paths to further improvement. Adv. Energy Mater. 3:864–72 [Google Scholar]
  115. Carsten B, Szarko JM, Lu L, Son HJ, He F. 115.  et al. 2012. Mediating solar cell performance by controlling the internal dipole change in organic photovoltaic polymers. Macromolecules 45:6390–95 [Google Scholar]
  116. Collins BA, Cochran JE, Yan H, Gann E, Hub C. 116.  et al. 2012. Polarized X-ray scattering reveals non-crystalline orientational ordering in organic films. Nat. Mater. 11:536–43 [Google Scholar]
  117. Bakuln AA, Rao A, Pavelyev VG, van Loosdrecht PHM, Pschenichnikov MS. 117.  et al. 2012. The role of driving energy and delocalized states for charge separation in organic semiconductors. Science 335:1340–44 [Google Scholar]
  118. Okada R, Toyoshima Y, Fujita H. 118.  1963. Viscometric test of the theory of Kurata, Stockmayer and Roig for the expansion of a polymer molecule. Die Makromol. Chem. 59:137–49 [Google Scholar]
  119. van Krevelen DW, te Nijenhuis K. 119.  2009. Properties of Polymers: Their Correlation with Chemical Structure; Their Numerical Estimation and Prediction from Additive Group Contributions Amsterdam: Elsevier Sci.
  120. Hays JB, Magar ME, Zimm BH. 120.  1969. Persistence length of DNA. Biopolymers 8:531–36 [Google Scholar]
  121. Chabinyc ML. 121.  2008. X-ray scattering from films of semiconducting polymers. Polym. Rev. 48:463–92 [Google Scholar]
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Phase Separation in Bulk Heterojunctions of Semiconducting Polymers and Fullerenes for Photovoltaics
Annual Review of Physical Chemistry 65, 59 (2014); https://doi.org/10.1146/annurev-physchem-040513-103712
/content/journals/10.1146/annurev-physchem-040513-103712
/content/journals/10.1146/annurev-physchem-040513-103712
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  • Article Type: Review Article

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