Low-Vapor-Pressure Solvent Additives Function as Polymer Swelling Agents in Bulk Heterojunction Organic Photovoltaics

Journal Article · Mon Jul 02 00:00:00 EDT 2018 · Journal of Physical Chemistry. C

DOI:https://doi.org/10.1021/acs.jpcc.8b04192· OSTI ID:1469065

Fontana, Matthew T. ^[1]; Kang, Hyeyeon ^[1]; Yee, Patrick Y. ^[1]; Fan, Zongwu ^[1]; Hawks, Steven A. ^[2]; Schelhas, Laura T. ^[3]; Subramaniyan, Selvam ^[4]; Hwang, Ye -Jin ^[5]; Jenekhe, Samson A. ^[4]; Tolbert, Sarah H. ^[1]; Schwartz, Benjamin J. ^[1]

---

1. Univ. of California, Los Angeles, CA (United States)
2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
3. SLAC National Accelerator Lab., Menlo Park, CA (United States)
4. Univ. of Washington, Seattle, WA (United States)
5. Inha Univ., Incheon (South Korea)

Here, bulk heterojunction (BHJ) photovoltaics based on blends of conjugated polymers and fullerenes require an optimized nanoscale morphology. Casting BHJ films using solvent additives such as 1,8-diiodooctane (DIO), 1,8-octanedithiol (ODT), chloronapthalene (CN), or diphenyl ether (DPE) often helps achieve this proper morphology: adding just a few volume percent of additive to the casting solution can improve polymer/fullerene mixing or phase separation, so that solvent additives have become staples in producing high-efficiency BHJ solar cells. The mechanism by which these additives improve BHJ morphology, however, is poorly understood. Here, we investigate how these additives control polymer/fullerene mixing by taking advantage of sequential processing (SqP), in which the polymer is deposited first and then the fullerene is intercalated into the polymer underlayer in a second processing step using a quasi-orthogonal solvent. In this way, SqP isolates the role of the additives’ interactions with the polymer and the fullerene.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE; USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC02-76SF00515; AC52-07NA27344
• OSTI ID: 1469065
• Alternate ID(s): OSTI ID: 1572612
• Report Number(s): LLNL-JRNL--769839
• Journal Information: Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 29 Vol. 122; ISSN 1932-7447
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

1
8-diiodooctane
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Energy - Solar
Polymer Swelling
Sequential-Processing
Solvent Additives
Swelling Agents