Nitroxide Radicals as Highly Reactive Redox Mediators in Dye‐Sensitized Solar Cells

Kato, Fumiaki; Kikuchi, Akitomo; Okuyama, Takumi; Oyaizu, Kenichi; Nishide, Hiroyuki

doi:10.1002/ange.201205036

Cited by 42 publications

(25 citation statements)

References 41 publications

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“…A polynorbornenepolythiophene hybrid has been obtained by preparing polynorbornene Scheme 3 Poly(TEMPO-substituted norbornene) crosslinked with electropolymerized polyaniline (5) and photodimerized coumarin 37 (6).…”

Section: Resultsmentioning

confidence: 99%

“…1-5 When the redox-active sites are electrochemically reversible [6][7][8][9] and are bound to a polymer chain, an electron self-exchange reaction between the neighboring sites effects the redox mediation through the polymer layer, which requires that electroneutralization by electrolyte ions is accomplished throughout the layer to maintain the electroactivity. [10][11][12] Aliphatic, or non-conjugated polymers populated with organic robust radicals such as nitroxide, [13][14][15][16][17][18][19][20][21][22][23] nitronyl nitroxide, 24,25 spirobisnitroxide 26 and galvinoxyl 27,28 have been found to be the typical examples, and their ideal redox-mediating properties 29 are different from those of conventional redox polymers such as poly (vinylferrocene), [30][31][32][33] which has been dominated by the 'break-in effect' of the electroneutralizing ions to give rise to limited charge capacity and hysteresis during the charging/discharging process.…”

Section: Introductionmentioning

confidence: 99%

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Facile charge transport and storage by a TEMPO-populated redox mediating polymer integrated with polyaniline as electrical conducting path

Oyaizu

Tatsuhira

Nishide

2014

Polym J

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A copolymer of TEMPO-and aniline-substituted norbornene was prepared by ring-opening metathesis polymerization of the corresponding monomers. Electropolymerization of the pendant aniline groups in the copolymer gave a layer of polynorbornene populated with the redox-active TEMPO pendants, in which polyaniline chain was incorporated. Electroactivity of the TEMPO pendants throughout the layer and its excellent charging/discharging cyclability, in addition to the amorphous nature of the layer, suggested that the polyaniline chain was homogeneously dispersed in the layer and that each chain served as crosslinking moiety. The effect of the polyaniline chains was further enhanced when they were formed by in-situ electropolymerization of the aniline group in the preformed layer of the copolymer/polyaniline composite. The polyaniline chain served as a conducting path to reduce the charge-transfer resistance for redox mediation, which gave rise to an excellent rate performance for the charging/ discharging process of the layer, compared with those for the composite layers of TEMPO-substituted polymers with polyaniline and other conductive additives prepared by the conventional grinding methods.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Facile charge transport and storage by a TEMPO-populated redox mediating polymer integrated with polyaniline as electrical conducting path

Oyaizu

Tatsuhira

Nishide

2014

Polym J

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“…They are free radicals themselves, but they are stable because of resonance structure involving the unpaired electron and steric hindrance from side chains. 73 The nitroxide radicals-containing …”

Section: Radical-scavengersmentioning

confidence: 99%

The Quest for Nonthrombotic Surface Modifications to Achieve Hemocompatibility of Implantable Devices

Tchouta

Bonde

2015

ASAIO Journal

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The use of blood-contacting implantable devices is limited by surface-induced thrombosis, which has led to the development of thromboresistant surfaces. Multidisciplinary efforts have promoted the development of surface modifications to minimize thrombosis by targeting surface-induced coagulation. To this date, no material has been identified that remains irrevocably hemocompatible with time but many options are now available with their own limitations. Essential to this review is the understanding of some of the challenges in this field and newer opportunities for hemocompatibility research. This report will also briefly review many of the achievements in the development of hemocompatible biomaterial coating, including surface modifications against protein adsorption and platelet adhesion, biomimetism, and endothelialization.

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“…This reflects the high reactivity and high diffusivity for the JC-IL electrolyte and may increase J SC and the fill factor (FF) in DSSCs. [11] Photovoltaic performance Photocurrrent-voltage (J-V) curves of the DSSCs that use electrolytes with different redox couples measured under AM 1.5G illumination are shown in Figure 7 a. The corresponding photovoltaic parameters are given in Table 2, and all data are aver- aged from three independent DSSC devices under the same experimental conditions.…”

Section: Electrochemical Propertiesmentioning

confidence: 99%

“…[10] Nishide's group studied a series of TEMPO derivatives and found a compound named 2-azaadamantan-N-oxyl (AZA) as a substitute for TEMPO. [11] The difference between TEMPO and AZA comes from the rigid and symmetric adamantane structure of AZA that inhibits the elimination of the substituted protons. All of the redox couples that contain nitroxide radicals have more positive redox potentials than the I À /I 3 À redox couple.…”

Section: Introductionmentioning

confidence: 99%

Ionic Liquid with a Dual‐Redox Couple for Efficient Dye‐Sensitized Solar Cells

et al. 2013

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A new type of ionic liquid that contains a nitroxide radical (N-O(.)) and iodide as two redox couples, JC-IL, has been successfully synthesized for high-performance dye-sensitized solar cells (DSSCs). Both of the redox couples exhibit distinct redox potentials and attractive electrochemical characteristics. The UV/Vis absorption spectra of JC-IL shows a low-intensity peak compared to the strong absorption of I2 in the wavelength region of 350-500 nm. The high open-circuit voltage of DSSCs with JC-IL is over 850 mV, which is approximately 150 mV higher than that of the DSSCs with a standard iodide electrolyte. The dramatic increase in the standard heterogeneous electron-transfer rate constant leads to an increase in the short-circuit current for JC-IL compared to that of 2,2,6,6-tetramethylpiperidin-N-oxyl (TEMPO). DSSCs with the JC-IL electrolyte show promising cell efficiencies if coupled with dyes CR147 (8.12%) or D149 (6.76%). The efficiencies of the DSSCs based on the JC-IL electrolyte are higher than those of DSSCs based on either TEMPO electrolyte or standard iodide electrolyte alone.

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Nitroxide Radicals as Highly Reactive Redox Mediators in Dye‐Sensitized Solar Cells

Cited by 42 publications

References 41 publications

Facile charge transport and storage by a TEMPO-populated redox mediating polymer integrated with polyaniline as electrical conducting path

Facile charge transport and storage by a TEMPO-populated redox mediating polymer integrated with polyaniline as electrical conducting path

The Quest for Nonthrombotic Surface Modifications to Achieve Hemocompatibility of Implantable Devices

Ionic Liquid with a Dual‐Redox Couple for Efficient Dye‐Sensitized Solar Cells

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