Crystal-structure of active layers of small molecule organic photovoltaics before and after solvent vapor annealing

Berlinghof M, Langner S, Harreiß C, Schmidt E, Siris R, Bertram F, Shen C, Will J, Schindler T, Prihoda A, Rechberger S, Duesberg G, Neder R, Spiecker E, Brabec C, Unruh T (2020)


Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2020

Journal

Book Volume: 235

Pages Range: 15-28

Journal Issue: 1-2

DOI: 10.1515/zkri-2019-0055

Abstract

It is demonstrated by a detailed structural analysis that the crystallinity and the efficiency of small molecule based organic photovoltaics can be tuned by solvent vapor annealing (SVA). Blends made of the small molecule donor 2,2′-[(3,3′″,3″″,4′-tetraoctyl[2,2′:5′,2″:5″,2′″:5′″,2″″-quinquethiophene]-5,5″″-diyl)bis[(Z)-methylidyne(3-ethyl-4-oxo-5,2-thiazolidinediylidene)]]bis-propanedinitrile (DRCN5T) and the acceptor [6,6]-phenyl C71 butyric acid methyl ester (PC 71 BM) were annealed using solvent vapors with either a high solubility for the donor (tetrahydrofuran), the acceptor (carbon disulfide) or both (chloroform). The samples were analyzed by grazing-incidence wide-angle X-ray scattering (GIWAXS), electron diffraction, X-ray pole figures, and time-of-flight secondary ion mass spectrometry (ToF-SIMS). A phase separation of DRCN5T and PC 71 BM is induced by SVA leading to a crystallization of DRCN5T and the formation of a DRCN5T enriched layer. The DRCN5T crystallites possess the two dimensional oblique crystal system with the lattice parameters a = 19.2 Å, c = 27.1 Å, and β = 111.1° for the chloroform case. No major differences in the crystal structure for the other solvent vapors were observed. However, the solvent choice strongly influences the size of the DRCN5T enriched layer. Missing periodicity in the [010]-direction leads to the extinction of all Bragg reflections with k ≠ 0. The annealed samples are randomly orientated with respect to the normal of the substrate (fiber texture).

Authors with CRIS profile

Additional Organisation(s)

Related research project(s)

Involved external institutions

How to cite

APA:

Berlinghof, M., Langner, S., Harreiß, C., Schmidt, E., Siris, R., Bertram, F.,... Unruh, T. (2020). Crystal-structure of active layers of small molecule organic photovoltaics before and after solvent vapor annealing. Zeitschrift fur Kristallographie - Crystalline Materials, 235(1-2), 15-28. https://dx.doi.org/10.1515/zkri-2019-0055

MLA:

Berlinghof, Marvin, et al. "Crystal-structure of active layers of small molecule organic photovoltaics before and after solvent vapor annealing." Zeitschrift fur Kristallographie - Crystalline Materials 235.1-2 (2020): 15-28.

BibTeX: Download