Nano-pathways: Bridging the divide between water-processable nanoparticulate and bulk heterojunction organic photovoltaics. (January 2016)

• Record Type: Journal Article
• Authors: Holmes, Natalie P.; Marks, Melissa; Kumar, Pankaj; Kroon, Renee; Barr, Matthew G.; Nicolaidis, Nicolas; Feron, Krishna; Pivrikas, Almantas; Fahy, Adam; Mendaza, Amaia Diaz de Zerio; Kilcoyne, A.L.David; Müller, Christian; Zhou, Xiaojing; Andersson, Mats R.; Dastoor, Paul C.; Belcher, Warwick J.
• Is Part Of: Nano energy. Volume 19(2016:Jan.)
• Page Start: 495
• Page End: 510
• Publication Date: 2016-01
• Subjects: Water processable solar cells -- Nanoparticle -- Organic photovoltaic -- Blend morphology -- Glass transition temperature -- Scanning transmission X-ray microscopy; BHJ bulk heterojunction -- DCB dichlorobenzene -- EQE external quantum efficiency -- FF fill factor -- ITO indium tin oxide -- JSC short circuit current density -- Mn number average molecular weight -- Mw weight average molecular weight -- NP-OPV nanoparticle organic photovoltaic -- P3HT poly(3-hexylthiophene) -- PC61BM (phenyl C61 butyric acid methyl ester) -- PC71BM (phenyl C71 butyric acid methyl ester) -- PCE power conversion efficiency -- PDI polydispersity -- PEDOT:PSS poly(3, 4-ethylenedioxythiophene) polystyrene sulphonate -- R2R roll-to-roll -- RPV Resistance dependent PhotoVoltage -- SDS sodium dodecyl sulphate -- SEC size exclusion chromatography -- SEM scanning electron microscopy -- Si3N4 silicon nitride -- STXM scanning transmission X-ray microscopy -- TEM transmission electron microscopy -- Tg glass transition temperature -- TQ1 poly[2, 3-bis-(3-octyloxyphenyl)quinoxaline-5, 8-diyl-alt-thiophene-2, 5-diyl] -- VOC open circuit voltage; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2015.11.021
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Here we report the application of a conjugated copolymer based on thiophene and quinoxaline units, namely poly[2, 3-bis-(3-octyloxyphenyl)quinoxaline-5, 8-diyl-alt-thiophene-2, 5-diyl] (TQ1), to nanoparticle organic photovoltaics (NP-OPVs). TQ1 exhibits more desirable material properties for NP-OPV fabrication and operation, particularly a high glass transition temperature (Tg ) and amorphous nature, compared to the commonly applied semicrystalline polymer poly(3-hexylthiophene) (P3HT). This study reports the optimisation of TQ1:PC71 BM (phenyl C71 butyric acid methyl ester) NP-OPV device performance by the application of mild thermal annealing treatments in the range of the Tg (sub-Tg and post-Tg ), both in the active layer drying stage and post-cathode deposition annealing stage of device fabrication, and an in-depth study of the effect of these treatments on nanoparticle film morphology. In addition, we report a type of morphological evolution in nanoparticle films for OPV active layers that has not previously been observed, that of PC71 BM nano-pathway formation between dispersed PC71 BM-rich nanoparticle cores, which have the benefit of making the bulk film more conducive to charge percolation and extraction. Graphical abstract: Highlights: NPs enable fabrication of OPVs from environmentally friendly water-based inks. TQ1:PC71 BM NPs show a superior level of morphological control in thin films. Bicontinuous percolation pathways throughout thin films can be achieved with NPs. Carefully annealing the high Tg material domains facilitates nano-pathway formation. PC71 BM nano-pathways bridge the divide between dispersed PC71 BM-rich NP cores.