Phase separation and affinity between a fluorinated perylene diimide dye and an alkyl-substituted hexa-peri-hexabenzocoronene

Abstract

Fluorination of alkyl groups is a known strategy for hindering miscibility, thus promoting phase separation, when blends are prepared with a hydrocarbon compound. A new perylene bis(dicarboximide) derivative functionalized with branched N-perfluoroalkyl moieties (BPF-PDI) has been synthesized as electron acceptor to be potentially used in conjunction with the electron donor hexakis(dodecyl)hexabenzocoronene (HBC-C 12 ) in bulk heterojunction solar cells. Aiming at controlling self-assembly between the two components at the supramolecular level, stoichiometric blends in CHCl 3 have been prepared either by spin-or drop-casting onto silicon surfaces, and further subjected to solvent vapour annealing (SVA) treatment in a CHCl 3 -saturated atmosphere. Spectroscopic investigation in solution shows the formation of supramolecular BPF-PDI-HBC-C 12 dimers, with an association constant K ass ¼ (2.1 AE 0.3) Â 10 4 M À1 , pointing to a strong and unexpected affinity between the two species within the mixture. Characterization through optical and atomic force microscopies of the deposited samples revealed that the self-assembly behaviour of the blends on SiO x is remarkably different from mono-component films, thus confirming the absence of a macroscopic phase-separation between the two components featuring isolated domains of the neat acceptor or donor compound. In addition, X-ray studies provided evidence for the existence of a local-scale phase separation. These findings are of importance for organic photovoltaics, since they offer a new strategy to control the phase separation at different scales in electron acceptor-donor blends.

Exfoliation of Few‐Layer Graphene in Volatile Solvents Using Aromatic Perylene Diimide Derivatives as Surfactants

“…Similar results were obtained with G‐PDI−H and G‐PDI−Cl in CHCl 3 dispersions. Optical absorption spectra of the G‐PDI−PVC multilayers showed the spectral signature of both graphene and PDI, similarly to those observed in dispersion (Figure S5, Supporting Information), with no significant shift in absorption …”

Non‐conventional Processing and Post‐processing Methods for the Nanostructuring of Conjugated Materials for Organic Electronics

“…This method would imply a tuning of the chemical properties of D and A molecules, which are complementary from the electronic point of view, so that the SVA step could selectively anneal only one blend component by favoring homomolecular aggregation. Therefore, a new PDI derivative functionalized with branched N ‐perfluoroalkyl moieties ( 16 ) has been synthesized to be blended with the electron donor hexadodecyl substituted HBC ( 1) (Figure 1a) 44. Unexpectedly, the two components interact very strongly in solution already, leading to a supramolecular dimer with a K ass = 10 4 M −1 .…”

“…h–j) 2D WAXS patterns for extruded samples of BPF‐PDI, HBC‐C 12 , and their 1:1 blend, respectively; dashed circles indicating characteristic reflections of the pure compounds related to intracolumnar packing of the molecules. b–j) Reproduced with permission 44. Copyright 2010, Royal Society of Chemistry.…”

Supramolecular electron donor–acceptor complexes formed by perylene diimide derivative and conjugated phenazines

“…It has been reported that the donor-acceptor complex of PDI can form needle-like nanostructure through attractive intermolecular hydrophobic interactions and the stacking of the aromatic core. 42 As for PASP/3a, a rod-like nanostructure can be observed with an average diameter of about 40-75 nm, and the average length of about 170-400 nm ( Fig. 7e and f).…”