Combinatorial Screening of Inkjet Printed Ternary Blends for Organic Photovoltaics: Absorption Behavior and Morphology

Abstract

Inkjet printing was used for the preparation of ternary polymer/polymer/fullerene layers for organic solar cell application, as part of a combinatorial setup for the preparation and characterization of thin-film libraries. Poly(phenylene-ethynylene)-alt-poly(phenylene-vinylene) (PPE-alt-PPV) and poly(diketopyrrolopyrrole-alt-fluorene) (P(DPP-alt-F)) were systematically blended with poly(3-octylthiophene) (P3OT) and investigated by UV-vis spectroscopy to improve the photon harvesting by extending the absorption range. The blends with the broadest absorption range (20 and 40 wt % of PPE-alt-PPV and P(DPP-alt-F), respectively) were mixed with mono(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C61 (PCBM). The blend with the low band gap polymer P(DPP-alt-F) revealed the most extended absorption, which ranges over the whole visible spectrum (350 to 750 nm). The mixing with PCBM (ratio 1/3) led to an optimal emission quenching and revealed a smooth film formation. In this contribution, we show that the combinatorial screening using inkjet printing represents an effective, time- and material-saving workflow for the investigation of polymer blend libraries, which is of high interest for the development of new materials for active layers in organic photovoltaics.

Accelerating organic solar cell material's discovery: high-throughput screening and big data

“…To partly circumvent this limitation, Teichler et al introduced a platform based on inkjet printing to demonstrate the combinatorial screening of polymer:fullerene 94 and polymer:polymer:fullerene 95 blends ( Fig. 7c ).…”

“…In this case, samples were prepared in the robotized laboratory shown in (a) by drop casting 93. (c) Inkjet printed array of ternary OPV blends for their combinatorial optimization in terms of extended light harvesting 95. (d) Representative workflow in a self-driven laboratory that merges automatic ink preparation and film casting, optoelectronic characterization and experiment planning in a closed-loop pipeline with the help of ChemOS and AI 110.…”

“…(d) Representative workflow in a self-driven laboratory that merges automatic ink preparation and film casting, optoelectronic characterization and experiment planning in a closed-loop pipeline with the help of ChemOS and AI 110. Figures reprinted with permission from ref 95. (Copyright 2013, American Chemical Society); and the authors 93,110.…”

Performance Evaluation of an Organic Thin-Film Solar Cell of PTB7:PC71BM with an Alcohol-Soluble Polyelectrolyte Interlayer Prepared Using the Spray-Coating Method

“…The effect of a PFN interlayer applied by the spin-coating method is to increase charge-transport properties, eliminate the accumulation of space charge, reduce recombination, and improve the PCE. ,,− However, this method is limited by the waste of high material consumption, and it is also not compatible with roll-to-roll or large-area manufacturing. To achieve large-area, cost-effective OTFSC devices, the spray-coating, , doctor-blading, − and ink-jet printing techniques are used. Of these, the spray-coating method is well-established in industrial coating processes for the low-cost and large-area reel-to-reel production of OTFSCs.…”

Inkjet Printing of a Benzocyclobutene-Based Polymer as a Low-k Material for Electronic Applications

“…The coffee ring effect occurs when the particles of the nonvolatile solute present in the ink pin to the substrate at the edge of the drop, while a capillary flow occurs from the center of the drop toward the edge, transporting the solute. , Several solutions have been found to avoid or control the coffee ring effect: proper choice of the solute particles (i.e., ellipsoidal shape), a bigger dimension of the solute particles, reducing substrate temperature, , use of appropriate additives and surfactants, , and inducing the Marangoni flow, which is driven by an interfacial surface tension gradient caused by the presence of two solvents with different boiling temperatures . In the literature, many works can be found on the inkjet printing of polymeric inks. − Bernasconi et al printed SU8-based inks on a Si wafer substrate. They were able to print complex patterns to be used as masks for metal electrodeposition.…”