Chlorine-free processed high performance organic solar cells

Synooka, Olesia; Eberhardt, K.-R.; Hoppe, Harald

doi:10.1039/c4ra01783h

Cited by 25 publications

(29 citation statements)

References 45 publications

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“…The highest performances, 6.11% in air and 7.15% under a nitrogen atmosphere, were reported by Tsai et al and Hoppe et al, respectively. [ 4,[36][37][38] Our results could be partly explained by a change in the nanomorphology of P3 :PC 61 BM BHJ with the addition of DPE, as shown in AFM images ( Figure S17, Supporting Information). Indeed, without an additive, relatively large domains (200-300 nm) were observed, indicating weak charge generation and transport.…”

Section: Doi: 101002/aenm201502094mentioning

confidence: 88%

New Processable Phenanthridinone‐Based Polymers for Organic Solar Cell Applications

Guérette

Najari

Maltais

et al. 2016

Advanced Energy Materials

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anionic form under the alkylation conditions. This same trend was observed for the alkylation of pyrido [2,3,4,5-lmn ]phenanthridine under basic conditions. [ 24 ] Owing to the different functional groups, M1 and M2 can be easily separated on a chromatographic column or purifi ed by recrystallization. To obtain low band gap and processable materials, these monomers were copolymerized with 2,5-bis(2-octyldodecyl)-3,6-di(thien-2-yl)pyrrolo [3,4-c ]pyrrole-1,4-dione ( M3 ) (see the Supporting Information). [ 25 ] The polymerization reactions are also described in Scheme 1 . Two alternating copolymers ( P1 and P2 ) and one random terpolymer ( P3 ) were synthesized via simple direct (hetero)arylation polymerization (DHAP) (see the Supporting Information), a "greener" method which has rapidly developed in recent years. [26][27][28] The advantages of DHAP are manifold, and include a reduction in the number of reaction steps and the elimination of toxic organometallic by-products. The polymerization conditions utilized here are based on a recent report which has shown a high selectivity between aryl-bromide and non-substituted thiophene units. [ 29 ] Suzuki cross-coupling polymerization reactions were also performed for comparison purposes (see the Supporting Information). All polymers are soluble in common chlorinated solvents, such as chloroform (CF) and o -dichlorobenzene (ODCB), as well as chlorine-free solvents such as o -xylene. Interestingly, it has been noted that P2 ( M n = 60 kDa, PDI = 4.0) always afforded higher molecular weights than P1 ( M n = 43 kDa, PDI = 4.0). This could be explained by the greater solubility of P2 . Finally, a terpolymer P3 was obtained by copolymerizing the resulting 35:65 mixture of M1 and M2 with one equivalent of M3 . With a high ratio (65%) of monomer M2 into the structure of the random terpolymer P3 , this polymer ( M n = 57 kDa, PDI = 2.9) displays a good solubility in common solvents. The electrochemical properties of the polymers were investigated by cyclic voltammetry (CV) and are reported in Figure 1 b and Table S1 (Supporting Information). The occupied and unoccupied molecular orbital (HOMO/ LUMO) levels of P1 , P2 , and P3 are −5.48/−3.93, −5.46/−3.95, and −5.43/−3.92 eV, respectively, which indicate good stability in air and similar electronic properties between polymers. As reported in Figure 1 , the pristine green polymers ( P1 , P2 , and P3 ) exhibit broad UV-vis absorption spectra with an optical band gap ( E g opt ) of 1.64-1.65 eV, which is in agreement with the measured electrochemical band gap ( E g elect = 1.51-1.55 eV). Thermogravimetric analyses revealed that all polymers are stable up to 400 °C ( Figure S11, Supporting Information). Also, differential scanning calorimetry (DSC) measurements indicate that all these non-symmetric polymers are amorphous, as no glass transition temperature is observed between 25 and 250 °C. The DSC results are corroborated by X-ray diffraction (XRD) measurements (see the Supporting Information).Organic solar cells (OSC) have attrac...

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Section: Doi: 101002/aenm201502094mentioning

confidence: 88%

New Processable Phenanthridinone‐Based Polymers for Organic Solar Cell Applications

Guérette

Najari

Maltais

et al. 2016

Advanced Energy Materials

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“…[4][5][6][7][8][9][10][11] While most reports in the literature have focused on the eco-friendliness of the main solvents, little attention has been paid to solvent additives which are often used to control the film drying in order to yield a favorable nano-morphology. Therefore, a strong need for alternative solvents has been recognized by the community, recently focussing on novel high-performance polymer:fullerene bulkheterojunction (BHJ) solar cells, deposited from nonchlorinated mono-, bis-or tris-substituted benzene analogues.…”

Section: Introductionmentioning

confidence: 99%

Highly efficient polymer solar cells cast from non-halogenated xylene/anisaldehyde solution

Sprau

Buss

Wagner

et al. 2015

Energy Environ. Sci.

139

113

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Several high performance polymer:fullerene bulk-heterojunction photo-active layers, deposited from the non-halogenated solvents o-xylene or anisole in combination with the eco-compatible additive p-anisaldehyde, are investigated. The respective solar cells yield excellent power conversion efficiencies up to 9.5%, outperforming reference devices deposited from the commonly used halogenated chlorobenzene/1,8-diiodooctane solvent/additive combination. The impact of the processing solvent on the bulk-heterojunction properties is exemplified on solar cells comprising benzodithiophenethienothiophene co-polymers and functionalized fullerenes (PTB7:PC71BM). The additive p-anisaldehyde improves film formation, enhances polymer order, reduces fullerene agglomeration and shows high volatility, thereby positively affecting layer deposition, improving charge carrier extraction and reducing drying time, the latter being crucial for future large area roll-to-roll device fabrication.

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“…[33][34][35][36][37][38][39][40][41][42][43][44][45] Of those, few were focused on improving the solubility of conjugated polymers via molecular design. 34,35,39,40,43,45 In general, three ways can be employed to increase the solubility of conjugated polymers.…”

Section: Introductionmentioning

confidence: 99%

Isoindigo-based low bandgap conjugated polymer for o-xylene processed efficient polymer solar cells with thick active layers

et al. 2015

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A low bandgap conjugated polymer, i.e., poly[2,2'-bithiophene-alt-7-fluoro-N,N'-bis(2-octyldodecyl)isoindigo] (P(1FIID-BT)), was synthesized. The polymer was soluble in non-chlorinated solvents such as o-xylene and mesitylene, and exhibited a film optical bandgap of 1.61 eV as calculated from absorption onset and a deep highest occupied molecular orbital (HOMO) energy level of -5.46 eV as measured by electrochemical method. Remarkably high mobilities of 0.33 and 0.42 cm 2 V -1 s -1 were obtained for organic field-effect transistors (OFETs) based on pristine and annealed films, respectively. Inverted polymer solar cells (PSCs) were fabricated with phenyl-C 61 -butyric acid methyl ester (PC 61 BM) as acceptor material and oxylene as processing solvent. The device efficiency was insensitive to the thickness of active layer, and all devices with film thickness in the range of 105-340 nm showed power conversion efficiency (PCE) higher than 6.5%. The devices based on 270 nm thick film displayed the highest performance with a V OC of 0.89 V, a J SC of 14.50 mA/cm 2 and a FF of 0.58, leading to a PCE of 7.46%. This is the first low bandgap conjugated polymer for PSCs which combine three features: non-chlorinated solvent processible, high efficiency and insensitivity of efficiency to active layer thickness. Recently, our group reported dithienocarbazole (DTC) and isoindigo (IID) based D-A low band gap conjugated polymers

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Chlorine-free processed high performance organic solar cells

Cited by 25 publications

References 45 publications

New Processable Phenanthridinone‐Based Polymers for Organic Solar Cell Applications

New Processable Phenanthridinone‐Based Polymers for Organic Solar Cell Applications

Highly efficient polymer solar cells cast from non-halogenated xylene/anisaldehyde solution

Isoindigo-based low bandgap conjugated polymer for o-xylene processed efficient polymer solar cells with thick active layers

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