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In situ characterization methods for evaluating microstructure formation and drying kinetics of solution-processed organic bulk-heterojunction films

Published online by Cambridge University Press:  26 May 2017

Nusret Sena Güldal ,
Thaer Kassar Open the ORCID record for Thaer Kassar [Opens in a new window] ,
Marvin Berlinghof ,
Tobias Unruh  and
Christoph J. Brabec
Nusret Sena Güldal*
Affiliation:
Materials for Energy Technology and Electronics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91058, Germany
Thaer Kassar
Affiliation:
Chair for Crystallography and Structural Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91058, Germany
Marvin Berlinghof
Affiliation:
Chair for Crystallography and Structural Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91058, Germany
Tobias Unruh
Affiliation:
Chair for Crystallography and Structural Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91058, Germany
Christoph J. Brabec
Affiliation:
Materials for Energy Technology and Electronics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91058, Germany; and Bavarian Center for Applied Energy Research (ZAE Bayern), Erlangen 91058, Germany
*
a)Address all correspondence to this author. e-mail: nsenaguldal@gmail.com
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Abstract

Recently, in situ characterization methods have attracted increasing attention, especially in organic photovoltaics (OPV) field, since they provide greater insight into the mechanism of film formation, thus help to identify optimized processing conditions used to process the most efficient organic bulk-heterojunction thin films. In combination with various powerful X-ray-based characterization methods, several studies observed the morphological changes under the influence of different processing conditions. In this review, we summarize the fundamentals and implementation of X-ray-based and optical characterization methods, utilized in in situ mode and introduce the reader a better overview of the information acquired from a given technique in terms of microstructure formation in OPV. While we give a chronological development of in situ characterization methods in the field of OPV, we discuss the interplay between thermodynamics of solutions and drying kinetics of different types of organic blends.

Keywords

microstructurephotovoltaicthin film
Type
Invited Reviews
Information
Journal of Materials Research , Volume 32 , Issue 10: Focus Issue: Microstructural Characterization for Emerging Photovoltaic Materials , 26 May 2017 , pp. 1855 - 1879
Copyright
Copyright © Materials Research Society 2017 

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Footnotes

Contributing Editor: Moritz Riede

This section of Journal of Materials Research is reserved for papers that are reviews of literature in a given area.

References

REFERENCES

Wöhrle, D. and Meissner, D.: Organic solar cells. Adv. Mater. 3(3), 129 (1991).CrossRefGoogle Scholar
Dou, L., You, J., Hong, Z., Xu, Z., Li, G., Street, R.A., and Yang, Y.: 25th anniversary article: A decade of organic/polymeric photovoltaic research. Adv. Mater. 25(46), 6642 (2013).CrossRefGoogle ScholarPubMed
Brabec, C.J., Sariciftci, N.S., and Hummelen, J.C.: Plastic solar cells. Adv. Funct. Mater. 11(1), 15 (2001).3.0.CO;2-A>CrossRefGoogle Scholar
Heeger, A.J.: 25th anniversary article: Bulk heterojunction solar cells: Understanding the mechanism of operation. Adv. Mater. 26(1), 10 (2014).CrossRefGoogle ScholarPubMed
Luo, G., Ren, X., Zhang, S., Wu, H., Choy, W.C.H., He, Z., and Cao, Y.: Recent advances in organic photovoltaics: Device structure and optical engineering optimization on the nanoscale. Small 12(12), 1547 (2016).CrossRefGoogle ScholarPubMed
Nelson, J.: Organic photovoltaic films. Mater. Today 5(5), 20 (2002).CrossRefGoogle Scholar
Koster, L.J.A., Shaheen, S.E., and Hummelen, J.C.: Pathways to a new efficiency regime for organic solar cells. Adv. Energy Mater. 2(10), 1246 (2012).CrossRefGoogle Scholar
Yu, G. and Heeger, A.J.: Charge separation and photovoltaic conversion in polymer composites with internal donor:acceptor heterojunctions. J. Appl. Phys. 78(7), 4510 (1995).CrossRefGoogle Scholar
Halls, J.J.M., Walsh, C.A., Greenham, N.C., Marseglia, E.A., Friend, R.H., Moratti, S.C., and Holmes, A.B.: Efficient photodiodes from interpenetrating polymer networks. Nature 376, 498 (1995).CrossRefGoogle Scholar
Brabec, C.J., Heeney, M., McCulloch, I., and Nelson, J.: Influence of blend microstructure on bulk heterojunction organic photovoltaic performance. Chem. Soc. Rev. 40(3), 1185 (2011).CrossRefGoogle ScholarPubMed
Zhao, J., Li, Y., Yang, G., Jiang, K., Lin, H., Ade, H., Ma, W., and Yan, H.: Efficient organic solar cells processed from hydrocarbon solvents. Nat. Energy 1(2), 15027 (2016).CrossRefGoogle Scholar
Heliatek (2016).Google Scholar
Scharber, M.C. and Sariciftci, N.S.: Efficiency of bulk-heterojunction organic solar cells. Prog. Polym. Sci. 38(12), 1929 (2013).CrossRefGoogle ScholarPubMed
DeLongchamp, D.M., Kline, R.J., and Herzing, A.: Nanoscale structure measurements for polymer-fullerene photovoltaics. Energy Environ. Sci. 5(3), 5980 (2012).CrossRefGoogle Scholar
Salleo, A., Kline, R.J., DeLongchamp, D.M., and Chabinyc, M.L.: Microstructural characterization and charge transport in thin films of conjugated polymers. Adv. Mater. 22(34), 3812 (2010).CrossRefGoogle ScholarPubMed
Yan, H., Collins, B.A., Gann, E., Wang, C., Ade, H., and Mcneill, C.R.: Correlating the efficiency and nanomorphology of polymer blend solar cells utilizing resonant soft X-ray scattering. ACS Nano 6(1), 677 (2012).CrossRefGoogle ScholarPubMed
Liao, H.C., Ho, C.C., Chang, C.Y., Jao, M.H., Darling, S.B., and Su, W.F.: Additives for morphology control in high-efficiency organic solar cells. Mater. Today 16(9), 326 (2013).CrossRefGoogle Scholar
Ma, W., Tumbleston, J.R., Wang, M., Gann, E., Huang, F., and Ade, H.: Domain purity, miscibility, and molecular orientation at donor:acceptor interfaces in high performance organic solar cells: Paths to further improvement. Adv. Energy Mater. 3(7), 864 (2013).CrossRefGoogle Scholar
Vandewal, K., Himmelberger, S., and Salleo, A.: Structural factors that affect the performance of organic bulk heterojunction solar cells. Macromolecules 46(16), 6379 (2013).CrossRefGoogle Scholar
Diao, Y., Shaw, L., and Mannsfeld, S.C.B.: Morphology control strategies for solution-processed organic semiconductor thin films. Energy Environ. Sci. 7(7), 2145 (2014).CrossRefGoogle Scholar
Treat, N.D. and Chabinyc, M.L.: Phase separation in bulk heterojunctions of semiconducting polymers and fullerenes for photovoltaics. Annu. Rev. Phys. Chem. 65, 59 (2014).CrossRefGoogle ScholarPubMed
Gasparini, N., Katsouras, A., Prodromidis, M.I., Avgeropoulos, A., Baran, D., Salvador, M., Fladischer, S., Spiecker, E., Chochos, C.L., Ameri, T., and Brabec, C.J.: Photophysics of molecular-weight-induced losses in indacenodithienothiophene-based solar cells. Adv. Funct. Mater. 25(30), 4898 (2015).CrossRefGoogle Scholar
Ro, H.W., Downing, J., Engmann, S., Herzing, A., DeLongchamp, D.M., Richter, L., Mukherjee, S., Ade, H., Abdelsamie, M., Amassian, A., Jagadamma, L.K., Yan, H., and Liu, Y.: Morphology changes upon scaling a high efficiency, solution-processed solar cell from spin-coating to roll-to-roll coating. Energy Environ. Sci. 9, 2835 (2016).CrossRefGoogle Scholar
Kouijzer, S., Michels, J.J., Van Den Berg, M., Gevaerts, V.S., Turbiez, M., Wienk, M.M., and Janssen, R.: Predicting morphologies of solution processed polymer:fullerene blends. J. Am. Chem. Soc. 135(32), 12057 (2013).CrossRefGoogle ScholarPubMed
Perez, L.A., Chou, K.W., Love, J.A., Van Der Poll, T.S., Smilgies, D.M., Nguyen, T.Q., Kramer, E.J., Amassian, A., and Bazan, G.C.: Solvent additive effects on small molecule crystallization in bulk heterojunction solar cells probed during spin casting. Adv. Mater. 25(44), 6380 (2013).CrossRefGoogle ScholarPubMed
Koerner, C., Elschner, C., Miller, N.C., Fitzner, R., Selzer, F., Reinold, E., Beuerle, P., Toney, M.F., McGehee, M.D., Leo, K., and Riede, M.: Probing the effect of substrate heating during deposition of DCV4T:C60 blend layers for organic solar cells. Org. Electron. 13(4), 623 (2012).CrossRefGoogle Scholar
Hegde, R., Henry, N., Whittle, B., Zang, H., Hu, B., Chen, J., Xiao, K., and Dadmun, M.: The impact of controlled solvent exposure on the morphology, structure and function of bulk heterojunction solar cells. Sol. Energy Mater. Sol. Cells 107, 112 (2012).CrossRefGoogle Scholar
Krebs, F.C.: Fabrication and processing of polymer solar cells: A review of printing and coating techniques. Sol. Energy Mater. Sol. Cells 93(4), 394 (2009).CrossRefGoogle Scholar
Shin, N., Richter, L.J., Herzing, A.A., Kline, R.J., and DeLongchamp, D.M.: Effect of processing additives on the solidification of blade-coated polymer fullerene blend films via in situ structure measurements. Adv. Energy Mater. 3(7), 938 (2013).CrossRefGoogle Scholar
Guo, S., Herzig, E.M., Naumann, A., Tainter, G., Perlich, J., and Müller-Buschbaum, P.: Influence of solvent and solvent additive on the morphology of PTB7 films probed via X-ray scattering. J. Phys. Chem. B 118(1), 344 (2014).CrossRefGoogle ScholarPubMed
Giri, G., Delongchamp, D.M., Reinspach, J., Fischer, D.A., Richter, L.J., Xu, J., Benight, S., Ayzner, A., He, M., Fang, L., Xue, G., Toney, M.F., and Bao, Z.: Effect of solution shearing method on packing and disorder of organic semiconductor polymers. Chem. Mater. 27(7), 2350 (2015).CrossRefGoogle Scholar
Harrick, N.J.: Determination of refractive index and film thickness from interference fringes. Appl. Opt. 10(10), 2344 (1971).CrossRefGoogle ScholarPubMed
Swanepoel, R.: Determination of the thickness and optical constants of amorphous silicon. J. Phys. E: Sci. Instrum. 16(12), 1214 (1983).CrossRefGoogle Scholar
Ficek, Z. and Swain, S.: Quantum Interference and Coherence, 1st ed. (Springer-Verlag, New York, 2005).Google Scholar
Campoy-Quiles, M., Schmidt, M., Nassyrov, D., Pena, O., Goni, A.R., Alonso, M.I., and Garriga, M.: Real-time studies during coating and post-deposition annealing in organic semiconductors. Thin Solid Films 519(9), 2678 (2011).CrossRefGoogle Scholar
Berne, B. and Pecora, R.: Dynamic Light Scattering-with Applications to Chemistry, Biology and Physics (Wiley Interscience, New York, 1976).Google Scholar
Zhao, K., Hu, H., Spada, E., Jagadamma, L.K., Yan, B., Abdelsamie, M., Yang, Y., Yu, L., Munir, R., Li, R., Ndjawa, G.O.N., and Amassian, A.: Highly efficient polymer solar cells with printed photoactive layer:rational process transfer from spin-coating. J. Mater. Chem. A 4, 16036 (2016).CrossRefGoogle Scholar
Abdelsamie, M., Zhao, K., Niazi, M.R., Chou, K.W., and Amassian, A.: In situ UV-visible absorption during spin-coating of organic semiconductors: A new probe for organic electronics and photovoltaics. J. Mater. Chem. C 2(17), 3373 (2014).CrossRefGoogle Scholar
Woollam, J.A.: Wiley Encycl. Electr. Electron. Eng. (John Wiley & Sons, Inc., Hoboken, 2001).Google Scholar
Losurdo, M. and Hingerl, K.: Ellipsometry at the Nanoscale, 1st ed. (Springer-Verlag, Berlin, Heidelberg, 2013).CrossRefGoogle Scholar
Tompkins, H.G. and Irene, E.A.: Handbook of Ellipsometry, 1st ed. (William Andrew Inc, Norwich, 2005).CrossRefGoogle Scholar
Weik, M.: Fiber Optics Standard Dictionary, 3rd ed. (Springer Science+Business Media, New York, 1997).CrossRefGoogle Scholar
Hinrichs, K. and Eichhorn, K.J.: Ellipsometry of Functional Organic Surfaces and Films, 1st ed. (Springer-Verlag, Berlin, Heidelberg, 2014).CrossRefGoogle Scholar
Lakowicz, J.R.: Principles of Fluorescence Spectroscopy Principles of Fluorescence Spectroscopy (Springer, New York, 2006).CrossRefGoogle Scholar
Mikhnenko, O.V.: Singlet and Triplet Excitons in Organic Semiconductors (University of Groningen, Groningen, 2011).Google Scholar
Köhler, A. and Bässler, H.: Triplet states in organic semiconductors. Mater. Sci. Eng., R 66(4–6), 71 (2009).CrossRefGoogle Scholar
Yersin, H. and Finkenzeller, W.J.: Highly Effic. OLEDs with Phosphorescent Mater. (Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 2008); pp. 1–97.Google Scholar
Nguyen, T.Q., Martini, I.B., Liu, J., and Schwartz, B.J.: Controlling interchain interactions in conjugated polymers: The effects of chain morphology on exciton–exciton annihilation and aggregation in MEH-PPV films. J. Phys. Chem. B 104(2), 237 (2000).CrossRefGoogle Scholar
Güldal, N.S., Kassar, T., Berlinghof, M., Ameri, T., Osvet, A., Pacios, R., Li Destri, G., Unruh, T., and Brabec, C.J.: Real-time evaluation of thin film drying kinetics using an advanced, multi-probe optical setup. J. Mater. Chem. C 11, 2178 (2016).CrossRefGoogle Scholar
Wang, P., Collison, C.J., and Rothberg, L.J.: Origins of aggregation quenching in luminescent phenylenevinylene polymers. J. Photochem. Photobiol., A 144(1), 63 (2001).CrossRefGoogle Scholar
Engmann, S., Bokel, F.A., Ro, H.W., Delongchamp, D.M., and Richter, L.J.: Real-time photoluminescence studies of structure evolution in organic solar cells. Adv. Energy Mater. 6(10), 1 (2016).CrossRefGoogle Scholar
Diebold, M.P.: Application of Light Scattering to Coatings, 1st ed. (Springer International Publishing, Cham, 2014).CrossRefGoogle Scholar
Schaertl, W.: Light Scattering from Polymer Solutions and Nanoparticle (Springer, Berlin, Heidelberg, New York, 2007).Google Scholar
Teraoka, I.: Polymer Solutions—An Introduction to Physical Properties (John Wiley & Sons, Inc., New York, 2002).CrossRefGoogle Scholar
van Franeker, J.J., Turbiez, M., Li, W., Wienk, M.M., and Janssen, R.: A real-time study of the benefits of co-solvents in polymer solar cell processing. Nat. Commun. 6, 6229 (2015).CrossRefGoogle ScholarPubMed
Renaud, G., Lazzari, R., and Leroy, F.: Probing surface and interface morphology with grazing incidence small angle X-ray scattering. Surf. Sci. Rep. 64(8), 255 (2009).CrossRefGoogle Scholar
Chen, W., Nikiforov, M.P., and Darling, S.B.: Morphology characterization in organic and hybrid solar cells. Energy Environ. Sci. 5(8), 8045 (2012).CrossRefGoogle Scholar
Liu, F., Gu, Y., Shen, X., Ferdous, S., Wang, H-W., and Russell, T.P.: Characterization of the morphology of solution-processed bulk heterojunction organic photovoltaics. Prog. Polym. Sci. 38(12), 1990 (2013).CrossRefGoogle Scholar
Born, M. and Wolf, E.: Principles of Optics: Electromagnetic Theory of Propagation, Interference and Diffraction of Light, 7th ed. (Cambridge University Press, Cambridge, 1999).CrossRefGoogle Scholar
Giri, G., Li, R., Smilgies, D-M., Li, E.Q., Diao, Y., Lenn, K.M., Chiu, M., Lin, D.W., Allen, R., Reinspach, J., Mannsfeld, S.C.B., Thoroddsen, S.T., Clancy, P., Bao, Z., and Amassian, A.: One-dimensional self-confinement promotes polymorph selection in large-area organic semiconductor thin films. Nat. Commun. 5, 3573 (2014).CrossRefGoogle ScholarPubMed
Smilgies, D.M., Li, R., Giri, G., Chou, K.W., Diao, Y., Bao, Z., and Amassian, A.: Look fast: Crystallization of conjugated molecules during solution shearing probed in situ and in real time by X-ray scattering. Phys. Status Solidi RRL 7(3), 177 (2013).CrossRefGoogle Scholar
Sinha, S.K., Sirota, E.B., Garoff, S., and Stanley, H.B.: X-ray and neutron scattering from rough surfaces. Phys. Rev. B: Condens. Matter Mater. Phys. 38(4), 2297 (1988).CrossRefGoogle ScholarPubMed
Rauscher, M., Salditt, T., and Spohn, H.: Small-angle X-ray scattering under grazing incidence: The cross section in the distorted-wave Born approximation. Phys. Rev. B: Condens. Matter Mater. Phys. 52(23), 16855 (1995).CrossRefGoogle ScholarPubMed
Yoneda, Y.: Anomalous surface reflection of X-rays. Phys. Rev. 131(5), 2010 (1963).CrossRefGoogle Scholar
Jiang, Z., Lee, D.R., Narayanan, S., Wang, J., and Sinha, S.K.: Waveguide-enhanced grazing-incidence small-angle X-ray scattering of buried nanostructures in thin films. Phys. Rev. B: Condens. Matter Mater. Phys. 84(7), 75440 (2011).CrossRefGoogle Scholar
Wu, W-R., Jeng, U-S., Su, C-J., Wei, K-H., Su, M-S., Chiu, M-Y., Chen, C-Y., Su, W-B., Su, C-H., and Su, A-C.: Competition between fullerene aggregation and poly(3-hexylthiophene) crystallization upon annealing of bulk heterojunction solar cells. ACS Nano 5(8), 6233 (2011).CrossRefGoogle ScholarPubMed
Zhang, C., Mumyatov, A., Langner, S., Perea, J.D., Kassar, T., Min, J., Ke, L., Chen, H., Gerasimov, K.L., Anokhin, D.V., Ivanov, D.A., Ameri, T., Osvet, A., Susarova, D.K., Unruh, T., Li, N., Troshin, P., and Brabec, C.J.: Overcoming the thermal instability of efficient polymer solar cells by employing novel fullerene-based acceptors. Adv. Energy Mater. 7(3), 1601204 (2016).CrossRefGoogle Scholar
Roehling, J.D., Baran, D., Sit, J., Kassar, T., Ameri, T., Unruh, T., Brabec, C.J., and Moulé, A.J.: Nanoscale morphology of PTB7 based organic photovoltaics as a function of fullerene size. Sci. Rep. 6, 30915 (2016).CrossRefGoogle ScholarPubMed
Hexemer, A. and Müller Buschbaum, P.: Advanced grazing-incidence techniques for modern soft-matter materials analysis. IUCrJ 2(Pt 1), 106 (2015).CrossRefGoogle ScholarPubMed
Smilgies, D-M.: Scherrer grain-size analysis adapted to grazing-incidence scattering with area detectors. J. Appl. Crystallogr. 42(6), 1030 (2009).CrossRefGoogle ScholarPubMed
Rivnay, J., Mannsfeld, S.C.B., Miller, C.E., Salleo, A., and Toney, M.F.: Quantitative determination of organic semiconductor microstructure from the molecular to device scale. Chem. Rev. 112(10), 5488 (2012).CrossRefGoogle ScholarPubMed
Boudouris, B.W., Ho, V., Jimison, L.H., Toney, M.F., Salleo, A., and Segalman, R.A.: Real-time observation of poly(3-alkylthiophene) crystallization and correlation with transient optoelectronic properties. Macromolecules 44(17), 6653 (2011).CrossRefGoogle Scholar
Gomez, E.D., Barteau, K.P., Wang, H., Toney, M.F., and Loo, Y-L.: Correlating the scattered intensities of P3HT and PCBM to the current densities of polymer solar cells. Chem. Commun. 47(1), 436 (2011).CrossRefGoogle Scholar
Müller-Buschbaum, P.: A basic introduction to grazing incidence small angle X-ray scattering. In Applications of Synchrotron Light to Scattering and Diffraction in Materials and Life Sciences, Gomez, M., Nogales, A., Garcia-Gutierrez, M.C., and Ezquerra, T.A., eds. (Springer Berlin Heidelberg, Berlin, Heidelberg, 2009); pp. 61–89.CrossRefGoogle Scholar
Müller Buschbaum, P.: The active layer morphology of organic solar cells probed with grazing incidence scattering techniques. Adv. Mater. 26(46), 7692 (2014).CrossRefGoogle ScholarPubMed
Lazzari, R.: IsGISAXS: A program for grazing-incidence small-angle X-ray scattering analysis of supported islands. J. Appl. Crystallogr. 35(4), 406 (2002).CrossRefGoogle Scholar
Babonneau, D.: FitGISAXS: Software package for modelling and analysis of GISAXS data using IGOR Pro. J. Appl. Crystallogr. 43(4), 929 (2010).CrossRefGoogle Scholar
C. Durniak, M. Ganeva, G. Pospelov, W. Van Herck, and J. Wuttke: Www.bornagainproject.org (2015).Google Scholar
Kassar, T., Güldal, N.S., Berlinghof, M., Ameri, T., Kratzer, A., Schroeder, B.C., Destri, G.L., Hirsch, A., Heeney, M., McCulloch, I., Brabec, C.J., and Unruh, T.: Real-time investigation of intercalation and structure evolution in printed polymer:fullerene bulk heterojunction thin films. Adv. Energy Mater. 6(5), 1502025 (2016).CrossRefGoogle Scholar
Moons, E.: Conjugated polymer blends: Linking film morphology to performance of light emitting diodes and photodiodes. J. Phys. Condens. Matter 14(47), 12235 (2002).CrossRefGoogle Scholar
Granstrom, M., Petritsch, K., Arias, A.C., Lux, A., Andersson, M.R., and Friend, R.H.: Laminated fabrication of polymeric photovoltaic diodes. Nature 395(1994), 257 (1998).CrossRefGoogle Scholar
Jukes, P.C., Heriot, S.Y., Sharp, J.S., and Jones, R.A.L.: Time-resolved light scattering studies of phase separation in thin film semiconducting polymer blends during spin-coating. Macromolecules 38(6), 2030 (2005).CrossRefGoogle Scholar
McNeill, C.R. and Greenham, N.C.: Conjugated-polymer blends for optoelectronics. Adv. Mater. 21(38–39), 3840 (2009).CrossRefGoogle Scholar
Heriot, S.Y. and Jones, R.A.L.: An interfacial instability in a transient wetting layer leads to lateral phase separation in thin spin-cast polymer-blend films. Nat. Mater. 4(10), 782 (2005).CrossRefGoogle Scholar
Ebbens, S., Hodgkinson, R., Parnell, A.J., Dunbar, A., Martin, S.J., Topham, P.D., Clarke, N., and Howse, J.R.: In situ imaging and height reconstruction of phase separation processes in polymer blends during spin coating. ACS Nano 5(6), 5124 (2011).CrossRefGoogle ScholarPubMed
Gu, X., Yan, H., Kurosawa, T., Schroeder, B.C., Gu, K.L., Zhou, Y., To, J.W.F., Oosterhout, S.D., Savikhin, V., Molina-lopez, F., Tassone, C.J., Mannsfeld, S.C.B., Wang, C., Toney, M.F., and Bao, Z.: Comparison of the morphology development of polymer–fullerene and polymer–polymer solar cells during solution-shearing blade coating. Adv. Energy Mater. 6(22), 1601225 (2016).CrossRefGoogle Scholar
Holliday, S., Ashraf, R.S., Wadsworth, A., Baran, D., Yousaf, S.A., Nielsen, C.B., Tan, C-H., Dimitrov, S.D., Shang, Z., Gasparini, N., Alamoudi, M., Laquai, F., Brabec, C.J., Salleo, A., Durrant, J.R., and McCulloch, I.: High-efficiency and air-stable P3HT-based polymer solar cells with a new non-fullerene acceptor. Nat. Commun. 7, 11585 (2016).CrossRefGoogle ScholarPubMed
Earmme, T., Hwang, Y-J., Murari, N.M., Subramaniyan, S., and Jenekhe, S.A.: All-polymer solar cells with 3.3% efficiency based on naphthalene diimide-selenophene copolymer acceptor. J. Am. Chem. Soc. 135(40), 14960 (2013).CrossRefGoogle ScholarPubMed
Gao, L., Zhang, Z.G., Xue, L., Min, J., Zhang, J., Wei, Z., and Li, Y.: All-polymer solar cells based on absorption-complementary polymer donor and acceptor with high power conversion efficiency of 8.27%. Adv. Mater. 28(9), 1884 (2016).CrossRefGoogle ScholarPubMed
Li, S., Zhang, H., Zhao, W., Ye, L., Yao, H., Yang, B., Zhang, S., and Hou, J.: Green-solvent-processed all-polymer solar cells containing a perylene diimide-based acceptor with an efficiency over 6.5%. Adv. Energy Mater. 6(5), 1501991 (2016).CrossRefGoogle Scholar
Schmidt-Hansberg, B., Klein, M.F.G., Peters, K., Buss, F., Pfeifer, J., Walheim, S., Colsmann, A., Lemmer, U., Scharfer, P., and Schabel, W.: In situ monitoring the drying kinetics of knife coated polymer–fullerene films for organic solar cells. J. Appl. Phys. 106(12), 124501 (2009).CrossRefGoogle Scholar
Wang, T., Dunbar, A.D.F., Staniec, P.A., Pearson, A.J., Hopkinson, P.E., MacDonald, J.E., Lilliu, S., Pizzey, C., Terrill, N.J., Donald, A.M., Ryan, A.J., Jones, R.A.L., and Lidzey, D.G.: The development of nanoscale morphology in polymer:fullerene photovoltaic blends during solvent casting. Soft Matter 6(17), 4128 (2010).CrossRefGoogle Scholar
Sanyal, M., Schmidt-Hansberg, B., Klein, M.F.G., Colsmann, A., Munuera, C., Vorobiev, A., Lemmer, U., Schabel, W., Dosch, H., and Barrena, E.: In situ X-ray study of drying-temperature influence on the structural evolution of bulk-heterojunction polymer–fullerene solar cells processed by doctor-blading. Adv. Energy Mater. 1(3), 363 (2011).CrossRefGoogle Scholar
Sanyal, M., Schmidt-Hansberg, B., Klein, M.F.G., Munuera, C., Vorobiev, A., Colsmann, A., Scharfer, P., Lemmer, U., Schabel, W., Dosch, H., and Barrena, E.: Effect of photovoltaic polymer/fullerene blend composition ratio on microstructure evolution during film solidification investigated in real time by X-ray diffraction. Macromolecules 44(10), 3795 (2011).CrossRefGoogle Scholar
Chou, K.W., Yan, B., Li, R., Li, E.Q., Zhao, K., Anjum, D.H., Alvarez, S., Gassaway, R., Biocca, A., Thoroddsen, S.T., Hexemer, A., and Amassian, A.: Spin-cast bulk heterojunction solar cells: A dynamical investigation. Adv. Mater. 25(13), 1923 (2013).CrossRefGoogle Scholar
Schmidt-Hansberg, B., Sanyal, M., Klein, M.F.G., Pfaff, M., Schnabel, N., Jaiser, S., Vorobiev, A., Müller, E., Colsmann, A., Scharfer, P., Gerthsen, D., Lemmer, U., Barrena, E., and Schabel, W.: Moving through the phase diagram: Morphology formation in solution cast polymer–fullerene blend films for organic solar cells. ACS Nano 5(11), 8579 (2011).CrossRefGoogle ScholarPubMed
Engmann, S., Ro, W., Herzing, A., Snyder, C.R., Richter, L.J., Geraghty, B., and Jones, D.J.: Film morphology evolution during solvent vapor annealing of highly efficient small molecule donor/acceptor blends. J. Mater. Chem. A 4(40), 15511 (2016).CrossRefGoogle ScholarPubMed
Huang, Y., Kramer, E.J., Heeger, A.J., and Bazan, G.C.: Bulk heterojunction solar cells: Morphology and performance relationships. Chem. Rev. 114(14), 7006 (2014).CrossRefGoogle ScholarPubMed
Rogers, J.T., Schmidt, K., Toney, M.F., Bazan, G.C., and Kramer, E.J.: Time-resolved structural evolution of additive-processed bulk heterojunction solar cells. J. Am. Chem. Soc. 134(6), 2884 (2012).CrossRefGoogle ScholarPubMed
Peet, J., Kim, J.Y., Coates, N.E., Ma, W.L., Moses, D., Heeger, A.J., and Bazan, G.C.: Efficiency enhancement in low-bandgap polymer solar cells by processing with alkane dithiols. Nat. Mater. 6(7), 497 (2007).CrossRefGoogle ScholarPubMed
Machui, F., Maisch, P., Burgués-Ceballos, I., Langner, S., Krantz, J., Ameri, T., and Brabec, C.J.: Classification of additives for organic photovoltaic devices. ChemPhysChem 16(6), 1275 (2015).CrossRefGoogle ScholarPubMed
Güldal, N.S., Berlinghof, M., Kassar, T., Du, X., Jiao, X., Meyer, M., Ameri, T., Osvet, A., Li, N., Li-Destri, G., Fink, R.H.H., Ade, H., Unruh, T., and Brabec, C.J.: Controlling additive behavior to reveal an alternative morphology formation mechanism in polymer:fullerene bulk-heterojunctions. J. Mater. Chem. A 4(41), 16136 (2016).CrossRefGoogle Scholar
Richter, L.J., Delongchamp, D.M., Bokel, F.A., Engmann, S., Chou, K.W., Amassian, A., Schaible, E., and Hexemer, A.: In situ morphology studies of the mechanism for solution additive effects on the formation of bulk heterojunction films. Adv. Energy Mater. 5(3), 140975 (2015).CrossRefGoogle Scholar
Rossander, L.H., Zawacka, N.K., Dam, H.F., Krebs, F.C., and Andreasen, J.W.: In situ monitoring of structure formation in the active layer of polymer solar cells during roll-to-roll coating. AIP Adv. 4(8), 87105 (2014).CrossRefGoogle Scholar
Liu, F., Ferdous, S., Schaible, E., Hexemer, A., Church, M., Ding, X., Wang, C., and Russell, T.P.: Fast printing and in situ morphology observation of organic photovoltaics using slot-die coating. Adv. Mater. 27(5), 886 (2014).CrossRefGoogle ScholarPubMed
Park, S.H., Roy, A., Beaupre, S., Cho, S., Coates, N., Moon, J.S., Moses, D., Leclerc, M., Lee, K., and Heeger, A.J.: Bulk heterojunction solar cells with internal quantum efficiency approaching 100%. Nat. Photonics 3(5), 297 (2009).CrossRefGoogle Scholar
Pearson, A.J., Wang, T., Dunbar, A.D.F., Yi, H., Watters, D.C., Coles, D.M., Staniec, P.A., Iraqi, A., Jones, R.A.L., and Lidzey, D.G.: Morphology development in amorphous polymer:fullerene photovoltaic blend films during solution casting. Adv. Funct. Mater. 24(5), 659 (2014).CrossRefGoogle Scholar
Liu, Y., Zhao, J., Li, Z., Mu, C., Ma, W., Hu, H., Jiang, K., Lin, H., Ade, H., and Yan, H.: Aggregation and morphology control enables multiple cases of high-efficiency polymer solar cells. Nat. Commun. 5, 5293 (2014).CrossRefGoogle ScholarPubMed
van der Poll, T.S., Love, J.A., Nguyen, T-Q., and Bazan, G.C.: Non-basic high-performance molecules for solution-processed organic solar cells. Adv. Mater. 24(27), 3646 (2012).CrossRefGoogle ScholarPubMed
Zhang, Q., Kan, B., Liu, F., Long, G., Wan, X., Chen, X., Zuo, Y., Ni, W., Zhang, H., Li, M., Hu, Z., Huang, F., Cao, Y., Liang, Z., Zhang, M., Russell, T.P., and Chen, Y.: Small-molecule solar cells with efficiency over 9%. Nat. Photonics 9(1), 35 (2015).CrossRefGoogle Scholar
Engmann, S., Bokel, F.A., Herzing, A.A., Ro, H.W., Girotto, C., Caputo, B., Hoven, C.V., Schaible, E., Hexemer, A., DeLongchamp, D.M., and Richter, L.J.: Real-time X-ray scattering studies of film evolution in high performing small-molecule:fullerene organic solar cells. J. Mater. Chem. A 3(16), 8764 (2015).CrossRefGoogle Scholar
Abdelsamie, M., Treat, N.D., Zhao, K., McDowell, C., Burgers, M.A., Li, R., Smilgies, D-M., Stingelin, N., Bazan, G.C., and Amassian, A.: Toward additive-free small-molecule organic solar cells: roles of the donor crystallization pathway and dynamics. Adv. Mater. 27(45), 7285 (2015).CrossRefGoogle ScholarPubMed
McDowell, C., Abdelsamie, M., Zhao, K., Smilgies, D-M., Bazan, G.C., and Amassian, A.: Synergistic impact of solvent and polymer additives on the film formation of small molecule blend films for bulk heterojunction solar cells. Adv. Energy Mater. 5(18), 1501121 (2015).CrossRefGoogle Scholar
Kwon, S., Park, J.K., Kim, J., Kim, G., Yu, K., Lee, J., Jo, Y-R., Kim, B-J., Kang, H., Kim, J., Kim, H., and Lee, K.: In situ studies of the molecular packing dynamics of bulk-heterojunction solar cells induced by the processing additive 1-chloronaphthalene. J. Mater. Chem. A 3(15), 7719 (2015).CrossRefGoogle Scholar
Kwon, S., Kang, H., Lee, J., Lee, J., Hong, S., Kim, H., and Lee, K.: Effect of processing additives on organic photovoltaics: Recent progress and future prospects. Adv. Energy Mater., in press (2016).Google Scholar