Organic photovoltaic devices with enhanced efficiency processed from non-halogenated binary solvent blends

Abstract

ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. The development of processing routes to fabricate organic photovoltaic devices (OPVs) using nonhalogenated solvents is a necessary step towards their eventual commercialisation. To address this issue, Organic Photovoltaic Devices With Enhanced Efficiency Processedwe have used Hansen solubility parameter analysis to identify a non-halogenated solvent blend based on a mixture of carbon disulfide and acetone. This solvent blend was then used to deposit a donor-acceptor polymer -fullerene thin-film that was then used as the active layer of bulk-heterojunction OPV. For the benchmark polymer:fullerene system PCDTBT:PC 70 BM, a power conversion efficiency of 6.75% was achieved; a 20% relative improvement over reference cells processed using the chlorinated-solvent chlorobenzene. Improvements in device efficiency are attributed to an increase in electron and hole conductivity resulting from enhanced fullerene crystallisation; a property that leads to enhanced device efficiency through improved charge extraction.

Solvent Additives: Key Morphology‐Directing Agents for Solution‐Processed Organic Solar Cells

“…Until donor and acceptor molecules are designed that self‐assemble well from such green solvents, most pairs are likely to form nonoptimized BHJ morphologies as‐cast, which solvent additives could readily improve. In green‐processed OPVs, new additives have emerged that were not previously tenable: for example, efficiencies of 6.6% were recently reported for PCDTBT:PC 70 BM processed from carbon disulfide with acetone as a cosolvent . So far, these additives appear to operate via the same mechanisms described in Section , but this will need to be borne out by further in situ film formation studies.…”

Enhancing Performance of Large‐Area Organic Solar Cells with Thick Film via Ternary Strategy

“…Therefore, scholars have focused on developing solvents to replace chlorinated solvents. Few works show that the PCE of a device processed with chlorine‐free solvent is similar to that of its counterpart processed with chlorinated ones . Vogt and Li and co‐workers used binary chlorine‐free solvent mixtures to mimic the Hansen solubility parameters of chlorine analogs .…”

Does 1,8-diiodooctane affect the aggregation state of PC 71 BM in solution?

“…We were unable to resolve the R g for PC 71 BM in these solvents, due to a significant incoherent background component in these measurements (electronic supplementary material, table S2). To accurately measure the value for PC 71 BM, we have switched to the solvent carbon disulfide (CS 2 ), which has been used previously to make OPV devices without the need for halogenated solvents [ 28 ]. Again using SANS and fitting a Guinier function, we measure an R g value of 4.3 ± 0.1 Å ( figure 6 ).…”