Organic Solar Cells Using a High‐Molecular‐Weight Benzodithiophene–Benzothiadiazole Copolymer with an Efficiency of 9.4%

Subbiah, Jegadesan; Purushothaman, Balaji; Chen, Ming; Qin, Tianshi; Gao, Mei; Vak, Doojin; Scholes, Fiona H.; Chen, Xiwen; Watkins, Scott E.; Wilson, Gerard J.; Holmes, Andrew B.; Wong, Wallace W. H.; Jones, David J.

doi:10.1002/adma.201403080

Cited by 190 publications

(122 citation statements)

References 35 publications

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“…The bis-borylated product was isolated by precipitation on addition of isopropanol (IPA), and an analytically pure material isolated by filtration in excellent yields >90%, Scheme 4. This simplified purification is in direct contrast with reported procedures for the bis-iodinated or bis-stannylated analogues [20–21]. …”

Section: Resultsmentioning

confidence: 88%

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

Geraghty¹,

Lee²,

Subbiah³

et al. 2016

Beilstein J. Org. Chem.

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The synthesis of key 4-alkyl-substituted 5-(trimethylsilyl)thiophene-2-boronic acid pinacol esters 3 allowed a simplified alkylthiophene catenation process to access bis-, ter-, quater-, and quinquethiophene π-bridges for the synthesis of acceptor–π-bridge-donor– π-bridge-acceptor (A–π-D–π-A) electron donor molecules. Based on the known benzodithiophene-terthiophene-rhodanine (BTR) material, the BXR series of materials, BMR (X = M, monothiophene), BBR (X = B, bithiophene), known BTR (X = T, terthiophene), BQR (X = Q, quaterthiophene), and BPR (X = P(penta), quinquethiophene) were synthesised to examine the influence of chromophore extension on the device performance and stability for OPV applications. The BT x R (x = 4, butyl, and x = 8, octyl) series of materials were synthesised by varying the oligothiophene π-bridge alkyl substituent to examine structure–property relationships in OPV device performance. The devices assembled using electron donors with an extended chromophore (BQR and BPR) are shown to be more thermally stable than the BTR containing devices, with un-optimized efficiencies up to 9.0% PCE. BQR has been incorporated as a secondary donor in ternary blend devices with PTB7-Th resulting in high-performance OPV devices with up to 10.7% PCE.

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Section: Resultsmentioning

confidence: 88%

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

Geraghty¹,

Lee²,

Subbiah³

et al. 2016

Beilstein J. Org. Chem.

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“…In most BDT-BT copolymers, an aromatic unit such as thiophene or furan is used as a spacer between BDT and BT [13][14][16][17] . A PCE of 9.40% has been reported for a copolymer direct linking of BDT with BT unit 18 , however, the BDT in this reference is not a simple BDT, but have two thiophenes attached to the central benzene.…”

Section: Introductionmentioning

confidence: 93%

Improved Performance for Inverted Organic Photovoltaics via Spacer between Benzodithiophene and Benzothiazole in Polymers

Mohammad¹,

Chen²,

Mitul³

et al. 2015

J. Phys. Chem. C

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In this work, the effects of the spacer between benzo[1,2-b;3,4-b']dithiophene (BDT) and dialkoxybenzothiadiazole (ROBT) in polymers were investigated for applications in organic solar cells. Polymer PBDT-2T-ROBT has a bi-thiophene (2T) spacer between the BDT and ROBT units, while PBDT-ROBT is a direct copolymer of BDT and ROBT. The polymer/PC 70 BM solar cells using both polymers were fabricated and optimized via polymer/fullerene ratio, solvent, and solvent additives. The spacer has significantly improved solar cell performance from 1.28% (Voc =0.77 V, Jsc = 3.13 mA/cm 2 , FF = 53.11 %) to 5.11% (Voc =0.66 V, Jsc = 13.33 mA/cm 2 , FF = 58.12%). The x-ray diffraction (XRD) spectra show the PBDT-2T-ROBT/PC 70 BM blended film is semicrystalline while PBDT-ROBT/PC 70 BM film is amorphous. This indicates that the spacer facilitates polymer organization for higher carrier mobility in the film. The atomic force microscopy (AFM) topography and phase images show that PBDT-2T-ROBT/PC 70 BM films form fibrillar networks, while PBDT-ROBT/PC 70 BM films exhibit larger granular morphology. The photoinduced charge extraction by linearly increasing voltage (Photo-CELIV) measurements show thatPBDT-2T-ROBT/PC 70 BM has a mobility of 9.59×10 -5 cm 2 /Vs, which is higher than the mobility of 8.64×10 -5 cm 2 /Vs for PBDT-ROBT/PC 70 BM film.

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“…[1][2][3][4][5][6][7] With such a promising initial efficiency, the long-term performance of OSCs also needs to be considered. 8,9 Extrapolated lifetimes of 2-3 years are reported in glass-on-glass encapsulated OSCs using the polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) blended with [6,6]-phenyl-C 60 -butyric acid methyl ester (PCBM), 10 and lifetimes of 7-10 years are reported in encapsulated OSCs with the polymer poly[9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole) (PCDTBT) 11 and fullerene [6,6]phenyl-C 70 -butyric acid methyl ester (PC 71 BM). 12,13 When polymer solar cells made from PCDTBT and PC 71 BM are illuminated in an environment with less than 0.1 parts per million (ppm) oxygen and water, extrapolated lifetimes approaching 20 years are observed, 14 which rivals the lifetimes observed in some evaporated small-molecule solar cells.…”

Section: Introductionmentioning

confidence: 99%

Molecular Packing and Arrangement Govern the Photo-Oxidative Stability of Organic Photovoltaic Materials

et al. 2015

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For long-term performance chemically robust materials are desired for organic solar cells (OSCs). Illuminating neat films of OSC materials in air and tracking the rate of absorption loss, or photobleaching, can quickly screen a material's photo-chemical stability. In this report, we photobleach neat films of OSC materials including polymers, solution-processed oligomers, solution-processed small molecules, and vacuum-deposited small molecules. Across the materials we test, we observe photobleaching rates that span seven orders of magnitude. Furthermore, we find that the film morphology of any particular material impacts the observed photobleaching rate, and that amorphous films photobleach faster than crystalline ones. In an extreme case, films of amorphous rubrene photobleach at a rate 2500 times faster than polycrystalline films. When we compare density to photobleaching rate, we find that stability increases with density. We also investigate the relationship between backbone planarity and chemical reactivity. The polymer PBDTTPD is more photostable than its more twisted and less ordered furan derivitative, PBDFTPD. Finally, we relate our work to what is known about the chemical stability of structural polymers, organic pigments, and organic light emitting diode materials. For the highest chemical stability, planar materials that form dense, crystalline film morphologies should be designed for OSCs.

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Organic Solar Cells Using a High‐Molecular‐Weight Benzodithiophene–Benzothiadiazole Copolymer with an Efficiency of 9.4%

Cited by 190 publications

References 35 publications

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

Improved Performance for Inverted Organic Photovoltaics via Spacer between Benzodithiophene and Benzothiazole in Polymers

Molecular Packing and Arrangement Govern the Photo-Oxidative Stability of Organic Photovoltaic Materials

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