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Title: In Situ Analysis of Solvent and Additive Effects on Film Morphology Evolution in Spin-Cast Small-Molecule and Polymer Photovoltaic Materials

Abstract

To elucidate the details of film morphology/order evolution during spin-coating, solvent and additive effects are systematically investigated for three representative organic solar cell (OSC) active layer materials using combined in situ grazing incidence wide angle x-ray scattering (GIWAXS) and optical reflectance. Two archetypical semiconducting donor (p-type) polymers, P3HT and PTB7, and semiconducting donor small-molecule, p-DTS(FBTTh 2) 2 are studied using three neat solvents (chloroform, chlorobenzene, 1,2-dichlorobenzene) and four processing additives (1-chloronaphthalene, diphenyl ether, 1,8-diiodooctane, and 1,6-diiodohexane). In situ GIWAXS identifies several trends: 1) for neat solvents, rapid crystallization occurs that risks kinetically locking the material into multiple crystal structures or crystalline orientations; and 2) for solvent + additive processed films, morphology evolution involves sequential transformations on timescales ranging from seconds to hours, with key divergences dependent on additive/semiconductor molecular interactions. When π-planes dominate the additive/semiconductor interactions, both polymers and small molecule films follow similar evolutions, completing in 1–5 min. When side chains dominate the additive/semiconductor interactions, polymer film maturation times are up to 9 h, while initial crystallization times <10 s are observed for small-molecule films. In conclusion, this study offers guiding information on OSC donor intermediate morphologies, evolution timescales, and divergent evolutions that can inform OSC manufacture.

Authors:
 [1];  [2];  [1]; ORCiD logo [3]; ORCiD logo [1]
  1. Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry and the Argonne-Northwestern Solar Energy Research (ANSER) Center; Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division
  2. Argonne National Lab. (ANL), Argonne, IL (United States). X-Ray Science Division
  3. Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry and the Argonne-Northwestern Solar Energy Research (ANSER) Center
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); Qatar NPRP
OSTI Identifier:
1471497
Alternate Identifier(s):
OSTI ID: 1439115
Grant/Contract Number:  
AC02-06CH11357; SC0001059; FG02-08ER46536; 7-286-1-046; 0960140
Resource Type:
Accepted Manuscript
Journal Name:
Advanced Energy Materials
Additional Journal Information:
Journal Volume: 8; Journal Issue: 23; Journal ID: ISSN 1614-6832
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; 36 MATERIALS SCIENCE; additives; in situ GIWAXS; organic solar cells; polymer; spin-coating

Citation Formats

Manley, Eric F., Strzalka, Joseph, Fauvell, Thomas J., Marks, Tobin J., and Chen, Lin X. In Situ Analysis of Solvent and Additive Effects on Film Morphology Evolution in Spin-Cast Small-Molecule and Polymer Photovoltaic Materials. United States: N. p., 2018. Web. doi:10.1002/aenm.201800611.
Manley, Eric F., Strzalka, Joseph, Fauvell, Thomas J., Marks, Tobin J., & Chen, Lin X. In Situ Analysis of Solvent and Additive Effects on Film Morphology Evolution in Spin-Cast Small-Molecule and Polymer Photovoltaic Materials. United States. doi:10.1002/aenm.201800611.
Manley, Eric F., Strzalka, Joseph, Fauvell, Thomas J., Marks, Tobin J., and Chen, Lin X. Fri . "In Situ Analysis of Solvent and Additive Effects on Film Morphology Evolution in Spin-Cast Small-Molecule and Polymer Photovoltaic Materials". United States. doi:10.1002/aenm.201800611.
@article{osti_1471497,
title = {In Situ Analysis of Solvent and Additive Effects on Film Morphology Evolution in Spin-Cast Small-Molecule and Polymer Photovoltaic Materials},
author = {Manley, Eric F. and Strzalka, Joseph and Fauvell, Thomas J. and Marks, Tobin J. and Chen, Lin X.},
abstractNote = {To elucidate the details of film morphology/order evolution during spin-coating, solvent and additive effects are systematically investigated for three representative organic solar cell (OSC) active layer materials using combined in situ grazing incidence wide angle x-ray scattering (GIWAXS) and optical reflectance. Two archetypical semiconducting donor (p-type) polymers, P3HT and PTB7, and semiconducting donor small-molecule, p-DTS(FBTTh2)2 are studied using three neat solvents (chloroform, chlorobenzene, 1,2-dichlorobenzene) and four processing additives (1-chloronaphthalene, diphenyl ether, 1,8-diiodooctane, and 1,6-diiodohexane). In situ GIWAXS identifies several trends: 1) for neat solvents, rapid crystallization occurs that risks kinetically locking the material into multiple crystal structures or crystalline orientations; and 2) for solvent + additive processed films, morphology evolution involves sequential transformations on timescales ranging from seconds to hours, with key divergences dependent on additive/semiconductor molecular interactions. When π-planes dominate the additive/semiconductor interactions, both polymers and small molecule films follow similar evolutions, completing in 1–5 min. When side chains dominate the additive/semiconductor interactions, polymer film maturation times are up to 9 h, while initial crystallization times <10 s are observed for small-molecule films. In conclusion, this study offers guiding information on OSC donor intermediate morphologies, evolution timescales, and divergent evolutions that can inform OSC manufacture.},
doi = {10.1002/aenm.201800611},
journal = {Advanced Energy Materials},
number = 23,
volume = 8,
place = {United States},
year = {2018},
month = {5}
}

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Works referenced in this record:

When Function Follows Form: Effects of Donor Copolymer Side Chains on Film Morphology and BHJ Solar Cell Performance
journal, November 2010

  • Szarko, Jodi M.; Guo, Jianchang; Liang, Yongye
  • Advanced Materials, Vol. 22, Issue 48, p. 5468-5472
  • DOI: 10.1002/adma.201002687