Effective Approaches to Improve the Electrical Conductivity of PEDOT:PSS: A Review

Shi, Hui; Liu, Congcong; Jiang, Qinglin; Xu, Jingkun

doi:10.1002/aelm.201500017

Cited by 975 publications

(870 citation statements)

References 149 publications

(388 reference statements)

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“…Nowadays, poly (3,4-ethylenedioxythiopehene) or PEDOT has been the most studied conducting polymer due its high electronic (hole) conductivity (1000-4000 S/cm) [4][5][6], room-temperature stability [7], and remarkable thermoelectric properties with the highest figure of merit for organic materials [8][9][10][11]. Given the temperature dependence of conductivity σ (σ increases with the temperature T ) and the high degree of inherent disorder, it is generally accepted that the transport in doped conductive polymers is mediated by phonon-assisted hopping between the localized states [12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Insulator to semimetallic transition in conducting polymers

et al. 2016

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We report a multiscale modeling of electronic structure of a conducting polymer poly(3,4-ethylenedioxythiopehene) (PEDOT) based on a realistic model of its morphology. We show that when the charge carrier concentration increases, the character of the density of states (DOS) gradually evolves from the insulating to the semimetallic, exhibiting a collapse of the gap between the bipolaron and valence bands with the drastic increase of the DOS between the bands. The origin of the observed behavior is attributed to the effect of randomly located counterions giving rise to the states in the gap. These results are discussed in light of recent experiments. The method developed in this work is general and can be applied to study the electronic structure of other conducting polymers.

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Section: Introductionmentioning

confidence: 99%

Insulator to semimetallic transition in conducting polymers

et al. 2016

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“…Similar power factors were reported for C 60 samples doped with Cr 2 (hpp) 4 or W 2 (hpp) 4 (hpp = 1, 3, 4, 6, 7, 8-hexahydro-2H-pyrimido [1,2-a] pyrimidinato). 75 K and Rb-doped C 60 were also used as TE materials and Seebeck coefficients were used to determine the thermopower to be −11 and −18 μV.K −1 at 300 K. 76 Several other composites of C 60 77 have been investigated in terms of their TE properties processed by mechanical alloying and spark plasma sintering. Studies of fullerene derivatives C 60 and C 70 show comparable power factors to those achieved with charge transfer salts; i.e.…”

Section: N-type Organic Thermoelectric Materialsmentioning

confidence: 99%

Review—Organic Materials for Thermoelectric Energy Generation

Cowen

Atoyo

Carnie

et al. 2017

ECS J. Solid State Sci. Technol.

130

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Organic semiconductor materials have been promising alternatives to their inorganic counterparts in several electronic applications such as solar cells, light emitting diodes, field effect transistors as well as thermoelectric generators. Their low cost, light weight and flexibility make them appealing in future applications such as foldable electronics and wearable circuits using printing techniques. In this report, we present a mini-review on the organic materials that have been used for thermoelectric energy generation. The reduction in the effects of climate change, caused by the burning of fossil fuels, has recently been given increased emphasis by major world governments and it is therefore necessary to consider the efficiency of the methods we currently use to generate energy. It has previously been estimated that 63% of global energy consumption is wasted with the major form of this waste being heat.1,2 It is therefore important to develop methods of reconverting this wasted heat back in to useful forms of energy, such as electricity.Thermoelectric generators (TEG) are a promising technology which make use of a process known as the Seebeck effect for heat recovery. The Seebeck effect can be described as two dissimilar conductors or semiconductors connected thermally in parallel and electrically in series and exposed to a temperature gradient causing a difference in voltage between the two materials.3,4 In a TEG one p-type and one ntype semiconductor make use of the Seebeck effect by connecting one to the other electrically in series and thermally in parallel; a general device setup is shown in Figure 1. By connecting the two components, by a junction which is heated, the n-type component of the device transports electrons from the hot junction to a heat sink while the p-type material transports positively charged holes along the same direction of the temperature gradient. The reverse is also possible if the holes and electrons flow away from a cold connecting junction to a heated point at the end of each semiconductor, this induces a constant cooling at the junction through the Peltier effect. 4,5The quantification of the Seebeck effect, in a specific material, is given by the Seebeck coefficient, α, and is the open circuit voltage of a material subjected to a temperature gradient, commonly with units on the scale of μVK −1 to mVK −1 . 6 A materials overall efficiency in the conversion of heat to electricity is given by the dimensionless figure of merit, ZT, defined as,where σ is the electrical conductivity and κ is the thermal conductivity. [6][7][8] It is therefore necessary for thermoelectric materials to have a high electrical conductivity and a low thermal conductivity making electrically conducting metals inappropriate for thermoelectric applications due to their high thermal conductivities and low z E-mail: m.j.carnie@swansea.ac.uk; derya.baran@kaust.edu.sa; b.c.schroeder@qmul .ac.uk Seebeck coefficients. The ideal thermoelectric materials should be an electrical crystal to maximize σ and at the s...

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“…[1-8] Electrical conductivities exceeding 1000 S/cm have routinely been achieved through the development of efficient methods, in particular, the addition of polar solvents to aqueous PEDOT:PSS solutions; [9][10][11] however, the charge transport mechanism is still not well understood in spite of its widespread utilization. The electrical properties of PEDOT:PSS films are strongly related to their complicated macromolecular structures; hence, clarifying the correlations between their electrical and structural properties is an active area of investigation in polymer science.…”

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confidence: 99%

Mesoscopic 2D Charge Transport in Commonplace PEDOT:PSS Films

Honma

Itoh

Masunaga

et al. 2018

Adv Elect Materials

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The correlation between the transport properties and structural degrees of freedom of conducting polymers is a central concern in both practical applications and scientific research. In this study, we demonstrated the existence of mesoscopic two-dimensional (2D) coherent charge transport in poly(3,4-ethylenedioxythiophene):poly-(styrenesulfonate) (PEDOT:PSS) film by performing structural investigations and high-field magnetoconductance (MC) measurements in magnetic fields of up to 15 T. We succeeded in observing marked positive MCs reflecting 2D electronic states in a conventional drop-cast film. This low-dimensional feature is surprising, since PEDOT:PSS-a mixture of two different polymers-seems to be significantly different from crystalline 2D materials in the viewpoint of the structural inhomogeneity, especially in popular drop-cast thick films. The results of the structural experiments suggest that such 2D transport originates from the nanometer-scale self-assembled laminated structure, which is composed of PEDOT nanocrystals wrapped by insulating sheets consisting of amorphous PSSs. These results indicate that charge transport in the PEDOT:PSS film can be divided into two regimes: mesoscopic 2D coherent tunneling and macroscopic three-dimensional hopping among 2D states. Our findings elucidate the hieratical nature of charge transport in the PEDOT:PSS film, which could provide new insight into a recent engineering concern, i.e., the reduction of the out-of-plane conductance.Conductive polymers are becoming indispensable in both scientific research and practical applications because of their advantageous features, such as mechanical flexibility, low toxicity, and the potential for use in low-cost device fabrication via printing processes. In particular, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS, which is produced by doping PEDOT with PSS) is one of the most commonly used polymers owing to its beneficial electric and thermoelectric properties, good stability under ambient conditions, and visible-light transmittance in thin-film form.[1-8] Electrical conductivities exceeding 1000 S/cm have routinely been achieved through the development of efficient methods, in particular, the addition of polar solvents to aqueous PEDOT:PSS solutions; [9][10][11] however, the charge transport mechanism is still not well understood in spite of its widespread utilization. The electrical properties of PEDOT:PSS films are strongly related to their complicated macromolecular structures; hence, clarifying the correlations between their electrical and structural properties is an active area of investigation in polymer science.The anisotropic conductance, namely, the reduction of outof-plane conductivity, in highly conductive PEDOT:PSS films is one of the crucial issues that must be unraveled for future applications. [12][13][14][15][16][17] Previous studies have indicated that the out-of-plane conductivity tends to be significantly less than the in-plane conductivity. Nardes et al. [12] reported an anisotropy...

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Effective Approaches to Improve the Electrical Conductivity of PEDOT:PSS: A Review

Cited by 975 publications

References 149 publications

Insulator to semimetallic transition in conducting polymers

Insulator to semimetallic transition in conducting polymers

Review—Organic Materials for Thermoelectric Energy Generation

Mesoscopic 2D Charge Transport in Commonplace PEDOT:PSS Films

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