Hostname: page-component-76fb5796d-skm99 Total loading time: 0 Render date: 2024-04-25T11:57:46.065Z Has data issue: false hasContentIssue false

Characterization of chain alignment at buried interfaces using Mueller matrix spectroscopy

Published online by Cambridge University Press:  30 March 2020

Bryan H. Smith
Affiliation:
Department of Chemical Engineering, The Pennsylvania State University, University Park, PA16802, USA
Renxuan Xie
Affiliation:
Department of Chemical Engineering, The Pennsylvania State University, University Park, PA16802, USA
Wonho Lee
Affiliation:
Department of Chemical Engineering, The Pennsylvania State University, University Park, PA16802, USA
Dipendra Adhikari
Affiliation:
Department of Physics and Astronomy, The University of Toledo, Toledo, OH43606, USA Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH43606, USA
Nikolas J. Podraza
Affiliation:
Department of Physics and Astronomy, The University of Toledo, Toledo, OH43606, USA Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH43606, USA
Enrique D. Gomez*
Affiliation:
Department of Chemical Engineering, The Pennsylvania State University, University Park, PA16802, USA Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA16802, USA Materials Research Institute, The Pennsylvania State University, University Park, PA16802, USA
*
Address all correspondence to Enrique D. Gomez at edg12@psu.edu
Get access

Abstract

The stiffness of conjugated polymers should lead to chain alignment near buried interfaces, even if the polymer film is nominally amorphous. Although simulations predict that this alignment layer is approximately 1.5 times the persistence length, chain alignment at buried interfaces of amorphous polymers has not been experimentally measured. Using Mueller matrix spectroscopy, the optical response of regiorandom poly(3-hexylthiophene-2,5-diyl) (P3HT) was modeled in order to extract the aligned layer thickness. By approximating the optical properties of the aligned layer as that of regioregular P3HT, the data can be effectively modeled. When the film is thicker than 150 nm, optical properties are best described with a 4-nm aligned layer, which is quantitatively consistent with previous predictions.

Type
Research Letters
Copyright
Copyright © Materials Research Society 2020

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1.Leolukman, M. and Kim, S.H.: Effect of rubbing-induced polymer chain alignment on adhesion and friction of glassy polystyrene surfaces. Langmuir 21, 682 (2005).CrossRefGoogle ScholarPubMed
2.Li, J., Park, J.K., Moore, R.B., and Madsen, L.A.: Linear coupling of alignment with transport in a polymer electrolyte membrane. Nat. Mater. 10, 507 (2011).CrossRefGoogle Scholar
3.Zhang, W., Gomez, E.D., and Milner, S.T.: Surface-induced chain alignment of semiflexible polymers. Macromolecules 49, 963 (2016).CrossRefGoogle Scholar
4.Joseph Kline, R., McGehee, M.D., and Toney, M.F.: Highly oriented crystals at the buried interface in polythiophene thin-film transistors. Nat. Mater. 5, 222 (2006).CrossRefGoogle Scholar
5.Chen, J.Z.Y. and Sullivan, D.E.: Free energy of a wormlike polymer chain confined in a slit: crossover between two scaling regimes. Macromolecules 39, 7769 (2006).CrossRefGoogle Scholar
6.Chen, J.Z.Y., Sullivan, D.E., and Yuan, X.: Surface-induced liquid crystal transitions of wormlike polymers confined in a narrow slit. A mean-field theory. Macromolecules 40, 1187 (2007).CrossRefGoogle Scholar
7.Ivanov, V.A., Rodionova, A.S., An, E.A., Martemyanova, J.A., Stukan, M.R., Müller, M., Paul, W., and Binder, K.: Orientational ordering transitions of semiflexible polymers in thin films: a Monte Carlo simulation. Phys. Rev. E 84, 041810 (2011).CrossRefGoogle ScholarPubMed
8.Morse, D.C. and Fredrickson, G.H.: Semiflexible polymers near interfaces. Phys. Rev. Lett. 73, 3235 (1994).CrossRefGoogle ScholarPubMed
9.Zhang, W., Gomez, E.D., and Milner, S.T.: Using surface-induced ordering to probe the isotropic-to-nematic transition for semiflexible polymers. Soft Matter 12, 6141 (2016).CrossRefGoogle ScholarPubMed
10.Xiao, M., Jasensky, J., Zhang, X., Li, Y., Pichan, C., Lu, X., and Chen, Z.: Influence of the side chain and substrate on polythiophene thin film surface, bulk, and buried interfacial structures. Phys. Chem. Chem. Phys. 18, 22089 (2016).CrossRefGoogle ScholarPubMed
11.DeLongchamp, D.M., Lin, E.K., and Fischer, D.A.. Organic semiconductor structure and chemistry from near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. In Optics and Photonics (SPIE2005), 2005. p. 59400A.CrossRefGoogle Scholar
12.Wang, H., Gomez, E.D., Guan, Z., Jaye, C., Toney, M.F., Fischer, D.A., Kahn, A., and Loo, Y.-L.: Tuning contact recombination and open-circuit voltage in polymer solar cells via self-assembled monolayer adsorption at the organic–metal oxide interface. J. Phys. Chem. C 117, 20474 (2013).CrossRefGoogle Scholar
13.Gurau, M.C., Delongchamp, D.M., Vogel, B.M., Lin, E.K., Fischer, D.A., Sambasivan, S., and Richter, L.J.: Measuring molecular order in poly(3-alkylthiophene) thin films with polarizing spectroscopies. Langmuir 23, 834 (2007).CrossRefGoogle ScholarPubMed
14.Germack, D.S., Chan, C.K., Kline, R.J., Fischer, D.A., Gundlach, D.J., Toney, M.F., Richter, L.J., and DeLongchamp, D.M.: Interfacial segregation in polymer/fullerene blend films for photovoltaic devices. Macromolecules 43, 3828 (2010).CrossRefGoogle Scholar
15.Gujral, A., Gómez, J., Ruan, S., Toney, M.F., Bock, H., Yu, L., and Ediger, M.D.: Vapor-deposited glasses with long-range columnar liquid crystalline order. Chem. Mater. 29, 9110 (2017).CrossRefGoogle Scholar
16.Dalal, S.S., Walters, D.M., Lyubimov, I., de Pablo, J.J., and Ediger, M.D.: Tunable molecular orientation and elevated thermal stability of vapor-deposited organic semiconductors. Proc. Natl. Acad. Sci. USA 112, 4227 (2015).CrossRefGoogle ScholarPubMed
17.Gujral, A., O'Hara, K.A., Toney, M.F., Chabinyc, M.L., and Ediger, M.D.: Structural characterization of vapor-deposited glasses of an organic hole transport material with X-ray scattering. Chem. Mater. 27, 3341 (2015).CrossRefGoogle Scholar
18.Walters, D.M., Antony, L., de Pablo, J.J., and Ediger, M.D.: Influence of molecular shape on the thermal stability and molecular orientation of vapor-deposited organic semiconductors. J. Phys. Chem. Lett. 8, 3380 (2017).CrossRefGoogle ScholarPubMed
19.Campoy-Quiles, M., Ferenczi, T., Agostinelli, T., Etchegoin, P.G., Kim, Y., Anthopoulos, T.D., Stavrinou, P.N., Bradley, D.D.C., and Nelson, J.: Morphology evolution via self-organization and lateral and vertical diffusion in polymer: fullerene solar cell blends. Nat. Mater. 7, 158 (2008).CrossRefGoogle ScholarPubMed
20.DeLongchamp, D.M., Kline, R.J., Fischer, D.A., Richter, L.J., and Toney, M.F.: Molecular characterization of organic electronic films. Adv. Mater. 23, 319 (2011).CrossRefGoogle ScholarPubMed
21.DeLongchamp, D.M., Kline, R.J., Lin, E.K., Fischer, D.A., Richter, L.J., Lucas, L.A., Heeney, M., McCulloch, I., and Northrup, J.E.: High carrier mobility polythiophene thin films: structure determination by experiment and theory. Adv. Mater. 19, 833 (2007).CrossRefGoogle Scholar
22.Ramsdale, C.M. and Greenham, N.C.: Ellipsometric determination of anisotropic optical constants in electroluminescent conjugated polymers. Adv. Mater. 14, 212 (2002).3.0.CO;2-V>CrossRefGoogle Scholar
23.McCulloch, I., Heeney, M., Chabinyc, M.L., DeLongchamp, D., Kline, R.J., Cölle, M., Duffy, W., Fischer, D., Gundlach, D., and Hamadani, B.: Semiconducting thienothiophene copolymers: design, synthesis, morphology, and performance in thin-film organic transistors. Adv. Mater. 21, 1091 (2009).CrossRefGoogle Scholar
24.Ameri, T., Dennler, G., Waldauf, C., Denk, P., Forberich, K., Scharber, M.C., Brabec, C.J., and Hingerl, K.: Realization, characterization, and optical modeling of inverted bulk-heterojunction organic solar cells. J. Appl. Phys. 103, 084506 (2008).CrossRefGoogle Scholar
25.Burkhard, G.F., Hoke, E.T., and McGehee, M.D.: Accounting for interference, scattering, and electrode absorption to make accurate internal quantum efficiency measurements in organic and other thin solar cells. Adv. Mater. 22, 3293 (2010).CrossRefGoogle ScholarPubMed
26.Campoy-Quiles, M., Alonso, M.I., Bradley, D.D.C., and Richter, L.J.: Advanced ellipsometric characterization of conjugated polymer films. Adv. Funct. Mater. 24, 2116 (2014).CrossRefGoogle Scholar
27.Müller, C., Andersson, L.M., Peña-Rodríguez, O., Garriga, M., Inganäs, O., and Campoy-Quiles, M.: Determination of thermal transition depth profiles in polymer semiconductor films with ellipsometry. Macromolecules 46, 7325 (2013).CrossRefGoogle Scholar
28.Garcia-Caurel, E., De Martino, A., Gaston, J.-P., and Yan, L.: Application of spectroscopic ellipsometry and Mueller ellipsometry to optical characterization. Appl. Spectrosc. 67, 1 (2013).CrossRefGoogle ScholarPubMed
29.Campoy-Quiles, M., Etchegoin, P.G., and Bradley, D.D.C.: On the optical anisotropy of conjugated polymer thin films. Phys. Rev. B 72, 045209 (2005).CrossRefGoogle Scholar
30.Laskarakis, A., Logothetidis, S., Pavlopoulou, E., and Gioti, M.: Mueller matrix spectroscopic ellipsometry: formulation and application. Thin Solid Films 455, 43 (2004).CrossRefGoogle Scholar
31.Arruda, E.M. and Przybylo, P.A.: An investigation into the three-dimensional stress-birefringence-strain relationship in elastomers. Polym. Eng. Sci. 35, 395 (1995).CrossRefGoogle Scholar
32.Beiermann, B.A., Kramer, S.L.B., May, P.A., Moore, J.S., White, S.R., and Sottos, N.R.: The effect of polymer chain alignment and relaxation on force-induced chemical reactions in an elastomer. Adv. Funct. Mater. 24, 1529 (2014).CrossRefGoogle Scholar
33.Hugger, S., Thomann, R., Heinzel, T., and Thurn-Albrecht, T.: Semicrystalline morphology in thin films of poly (3-hexylthiophene). Colloid Polym. Sci. 282, 932 (2004).Google Scholar
34.Xie, R., Lee, Y., Aplan, M.P., Caggiano, N.J., Müller, C., Colby, R.H., and Gomez, E.D.: Glass transition temperature of conjugated polymers by oscillatory shear rheometry. Macromolecules 50, 5146 (2017).CrossRefGoogle Scholar
35.Vakhshouri, K., Kozub, D.R., Wang, C., Salleo, A., and Gomez, E.D.: Effect of miscibility and percolation on electron transport in amorphous poly(3-hexylthiophene)/phenyl-C61-butyric acid methyl ester blends. Phys. Rev. Lett. 108, 026601 (2012).CrossRefGoogle ScholarPubMed
36.Kuei, B. and Gomez, E.D.: Chain conformations and phase behavior of conjugated polymers. Soft Matter 13, 49 (2017).CrossRefGoogle Scholar
37.McCulloch, B., Ho, V., Hoarfrost, M., Stanley, C., Do, C., Heller, W.T., and Segalman, R.A.: Polymer chain shape of poly(3-alkylthiophenes) in solution using small-angle neutron scattering. Macromolecules 46, 1899 (2013).CrossRefGoogle Scholar
38.Zhang, W., Gomez, E.D., and Milner, S.T.: Predicting chain dimensions of semiflexible polymers from dihedral potentials. Macromolecules 47, 6453 (2014).CrossRefGoogle Scholar
39.Chen, C., An, I., Ferreira, G.M., Podraza, N.J., Zapien, J.A., and Collins, R.W.: Multichannel Mueller matrix ellipsometer based on the dual rotating compensator principle. Thin Solid Films 455, 14 (2004).CrossRefGoogle Scholar
40.Fujiwara, H., Koh, J., Rovira, P.I., and Collins, R.W.: Assessment of effective-medium theories in the analysis of nucleation and microscopic surface roughness evolution for semiconductor thin films. Phys. Rev. B 61, 10832 (2000).CrossRefGoogle Scholar
41.Wilbur, J.D., Gomez, E.D., Ellsworth, M.W., Garetz, B.A., and Balsara, N.P.: Thermoreversible changes in aligned and cross-linked block copolymer melts studied by two color depolarized light scattering. Macromolecules 45, 7590 (2012).CrossRefGoogle Scholar
42.Na, J.Y., Kang, B., Sin, D.H., Cho, K., and Park, Y.D.: Understanding solidification of polythiophene thin films during spin-coating: effects of spin-coating time and processing additives. Sci. Rep. 5, 13288 (2015).CrossRefGoogle ScholarPubMed
43.Chang, J.-F., Sun, B., Breiby, D.W., Nielsen, M.M., Sölling, T.I., Giles, M., McCulloch, I., and Sirringhaus, H.: Enhanced mobility of poly(3-hexylthiophene) transistors by spin-coating from high-boiling-point solvents. Chem. Mater. 16, 4772 (2004).CrossRefGoogle Scholar
44.Zhang, W., Milner, S.T., and Gomez, E.D.: Nematic order imposes molecular weight effect on charge transport in conjugated polymers. ACS Cent. Sci. 4, 413 (2018).CrossRefGoogle ScholarPubMed
45.Wang, C., Rivnay, J., Himmelberger, S., Vakhshouri, K., Toney, M.F., Gomez, E.D., and Salleo, A.: Ultrathin body poly(3-hexylthiophene) transistors with improved short-channel performance. ACS Appl. Mater. Interfaces 5, 2342 (2013).CrossRefGoogle ScholarPubMed
46.Smith, B.H., Clark, M.B., Kuang, H., Grieco, C., Larsen, A.V., Zhu, C., Wang, C., Hexemer, A., Asbury, J.B., Janik, M.J., and Gomez, E.D.: Controlling polymorphism in poly(3-hexylthiophene) through addition of ferrocene for enhanced charge mobilities in thin-film transistors. Adv. Funct. Mater. 25, 542 (2015).CrossRefGoogle Scholar
Supplementary material: PDF

Smith et al. supplementary material

Smith et al. supplementary material

Download Smith et al. supplementary material(PDF)
PDF 870.4 KB