Alternate donor-acceptor small-band-gap semiconducting polymers; Polysquaraines and polycroconaines

Havinga, E.; Hoeve, Wolter ten; Wynberg, Hans

doi:10.1016/0379-6779(93)90949-w

Cited by 419 publications

(366 citation statements)

References 14 publications

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“…The onset of the optical transition for charge transfer in these polymers marks the energy needed to generate free charge carriers and has been made as low as = 0.5 eV. 26,27 The mobility for these copolymers has been measured to be in the range 10 −5 -10 −3 cm 2 /Vs, 27 which is too large to find a substantial magnetic field effect. Localization of the charges to the monomeric units and a sufficiently low hopping rate could be achieved by inserting spacer units in between the monomers, as discussed above.…”

Section: Realization Of Suitable Systemsmentioning

confidence: 99%

Route towards huge magnetoresistance in doped polymers

Kersten¹,

Meskers²,

Bobbert³

2012

Phys. Rev. B

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Room-temperature magnetoresistance of the order of 10% has been observed in organic semiconductors. We predict that even larger magnetoresistance can be realized in suitably synthesized doped conjugated polymers. In such polymers, ionization of dopants creates free charges that recombine with a rate governed by a competition between an applied magnetic field and random hyperfine fields. This leads to a spin-blocking effect that depends on the magnetic field. We show that the combined effects of spin blocking and charge blocking, the fact that two free charges cannot occupy the same site, lead to a magnetoresistance of almost two orders of magnitude. This magnetoresistance occurs even at vanishing electric field and is therefore a quasiequilibrium effect. The influences of the dopant strength, energetic disorder, and interchain hopping are investigated. We find that the dopant strength and energetic disorder have only little influence on the magnetoresistance. Interchain hopping strongly decreases the magnetoresistance because it can lift spin-blocking and charge-blocking configurations that occur in strictly one-dimensional transport. We provide suggestions for realization of polymers that should show this magnetoresistance.

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Section: Realization Of Suitable Systemsmentioning

confidence: 99%

Route towards huge magnetoresistance in doped polymers

Kersten¹,

Meskers²,

Bobbert³

2012

Phys. Rev. B

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“…That same year Philips Electronics also submitted a patent application covering the polysquaraine derived from terthiophene 17 as a N-type conductive polymer [95]. Havinga, ten Hoeve and Wynberg further presented their idea in 1993 [96] of creating small band-gap polymers through the use of alternating donor and acceptor moieties along a conjugated polymer, hence the development of polysquaraines, which experimentally displayed band-gaps of ~1 eV and (undoped) electrical conductivities of 10 −7…”

Section: Electrical Propertiesmentioning

confidence: 99%

Pyrrolyl Squaraines–Fifty Golden Years

Lynch

2015

Metals

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Pyrrolyl squaraines, both dyes and polymers, were first reported in 1965 and since then a fascinating body of work has been produced investigating the chemistry of these interesting molecules. A major aspect of these molecules that makes them so appealing to those researchers who have contributed to this field over the last 50 years is their chemical versatility. In this review, subjects, such as the synthetic history, an understanding of the molecular structure, an overview of the optical properties, a discussion of both the electrical conduction properties, and magnetic properties, plus use of the particles of pyrrolyl squaraines, are presented. Furthermore, previously published results are not just presented; they are in certain cases collated and used to both highlight and explain important aspects of pyrrolyl squaraine chemistry.

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“…According to Havinga et al the low band gaps in polysquaraines can be due to the fact that their conjugated main chain with alternation of electron withdrawing and donating moieties represents the one-dimensional analogue of an n-i-p-i semiconductor structure in which the valence and the conduction bands are curved by space charge effects. 27 …”

Section: Donor-acceptor Systemsmentioning

confidence: 99%

Donor—Acceptor Type Low Band Gap Polymers: Polysquaraines and Related Systems

Ajayaghosh

2003

ChemInform

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In recent years, considerable effort has been directed towards the synthesis of conjugated polymers with low optical band gaps (E g ), since they show intrinsic electrical conductivity. One of the approaches towards the designing of such polymers is the use of strong donor and acceptor monomers at regular arrangements in the repeating units, which has limited success in many cases. An alternate strategy is the use of organic dyes, having inherently low HUMO-LUMO separation, as building blocks. Extension of conjugation in organic dyes is therefore expected to result in oligomers and polymers with near infrared absorption, which is a signature of low band gaps. Squaraine dyes are ideal candidates for this purpose due to their unique optical properties. This review highlights the recent developments in the area of donor-acceptor type low band gap polymers with special emphasis on polysquaraines.

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Alternate donor-acceptor small-band-gap semiconducting polymers; Polysquaraines and polycroconaines

Cited by 419 publications

References 14 publications

Route towards huge magnetoresistance in doped polymers

Route towards huge magnetoresistance in doped polymers

Pyrrolyl Squaraines–Fifty Golden Years

Donor—Acceptor Type Low Band Gap Polymers: Polysquaraines and Related Systems

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