scholarly journals Structure and Doping Optimization of IDT-Based Copolymers for Thermoelectrics

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1463
Author(s):  
Tongchao Liu ◽  
Dexun Xie ◽  
Jinjia Xu ◽  
Chengjun Pan
Keyword(s):  
Organic Semiconductors ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Room Temperature ◽  
Charge Carrier Transport ◽  
Structure Property ◽  
Polymer Backbone ◽  
Donor Acceptor ◽  
Higher Carrier Mobility ◽  
The Relationship

π-conjugated backbones play a fundamental role in determining the thermoelectric (TE) properties of organic semiconductors. Understanding the relationship between the structure–property–function can help us screen valuable materials. In this study, we designed and synthesized a series of conjugated copolymers (P1, P2, and P3) based on an indacenodithiophene (IDT) building block. A copolymer (P3) with an alternating donor–acceptor (D-A) structure exhibits a narrower band gap and higher carrier mobility, which may be due to the D-A structure that helps reduce the charge carrier transport obstacles. In the end, its power factor reaches 4.91 μW m−1 K−2 at room temperature after doping, which is superior to those of non-D-A IDT-based copolymers (P1 and P2). These results indicate that moderate adjustment of the polymer backbone is an effective way to improve the TE properties of copolymers.

scholarly journals Backbone Effects on the Thermoelectric Properties of Ultra-Small Bandgap Conjugated Polymers

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2486
Author(s):  
Dexun Xie ◽  
Jing Xiao ◽  
Quanwei Li ◽  
Tongchao Liu ◽  
Jinjia Xu ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Power Factor ◽  
Carrier Mobility ◽  
Polymeric Materials ◽  
Thermoelectric Performance ◽  
Organic Thermoelectric Materials ◽  
Higher Power ◽  
Donor Acceptor ◽  
Maximum Power Factor ◽  
Higher Carrier Mobility

Conjugated polymers with narrower bandgaps usually induce higher carrier mobility, which is vital for the improved thermoelectric performance of polymeric materials. Herein, two indacenodithiophene (IDT) based donor–acceptor (D-A) conjugated polymers (PIDT-BBT and PIDTT-BBT) were designed and synthesized, both of which exhibited low-bandgaps. PIDTT-BBT showed a more planar backbone and carrier mobility that was two orders of magnitude higher (2.74 × 10−2 cm2V−1s−1) than that of PIDT-BBT (4.52 × 10−4 cm2V−1s−1). Both exhibited excellent thermoelectric performance after doping with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, where PIDTT-BBT exhibited a larger conductivity (0.181 S cm−1) and a higher power factor (1.861 μW m−1 K−2) due to its higher carrier mobility. The maximum power factor of PIDTT-BBT reached 4.04 μW m−1 K−2 at 382 K. It is believed that conjugated polymers with a low bandgap are promising in the field of organic thermoelectric materials.

Electrophysical Properties of Iodine Doped Acetylene/Ethylene Copolymers

1993 ◽  
Vol 328 ◽  
Author(s):  
A. N. Aleshin ◽  
E. G. Guk ◽  
V. A. Marikhin ◽  
L. P. Myasnikova ◽  
D. G. Belov
Keyword(s):  
Thermal Properties ◽  
Charge Carrier ◽  
Carrier Transport ◽  
Room Temperature ◽  
Dc Conductivity ◽  
Charge Carrier Transport ◽  
Electrophysical Properties ◽  
Ethylene Copolymers ◽  
Hopping Mechanism ◽  
A Charge

ABSTRACTA new oxydative-resistant, fusible and processible ethylene/acetylene copolymer has been synthesized. The content of rigid (acetylene) and flexible (ethylene) fragments has been widely varied. The structure of the nascent powders and the films compressed at room temperature have been investigated by SEM and WAXS. DSC has been used for studying the thermal properties. DC conductivity of the iodine doped samples has been measured as a function of temperature. It is shown that the doping leads to arising conductivity in the samples even at 10 Mol % acetylene fragments in copolymer. The conductivity up to 10−3 S/cm is reached for the samples with acetylene fragment concentration about 20 Mol %. It is found that a charge carrier transport in investigated copolymers is caused by doped polyacetylene fragments and described by the hopping Mechanism.

Charge Carrier Transport along Grain Boundaries in Silicon

2013 ◽  
Vol 205-206 ◽  
pp. 293-298 ◽  
Author(s):  
Martin Kittler ◽  
Manfred Reiche ◽  
Hans Michael Krause
Keyword(s):  
Charge Carrier ◽  
Grain Boundaries ◽  
Carrier Transport ◽  
Room Temperature ◽  
Drain Current ◽  
Charge Carriers ◽  
Strong Increase ◽  
Charge Carrier Transport ◽  
Mobility Of Charge Carriers

The influence of GBs contained in the channel of MOS-FETs - fabricated in thin SOI layers - is demonstrated. The drain current measured at room temperature increases about 50 times for nFETs and about 10 times for pFETs, respectively, as compared to reference devices. The observations might be interpreted as a strong increase of the mobility of charge carriers. Moreover, the observed stepwise changes of the drain current at 5 K may point to Coulomb blockades.

Field Effect Mobility of F16PcCu Films in Various Gas Atmospheres

1999 ◽  
Vol 03 (07) ◽  
pp. 667-671 ◽  
Author(s):  
HIROKAZU TADA ◽  
HIROSHI TOUDA ◽  
MASAKI TAKADA ◽  
KAZUMI MATSUSHIGE
Keyword(s):  
Carrier Density ◽  
Field Effect ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Room Temperature ◽  
Gas Adsorption ◽  
Quick Recovery ◽  
Thermally Activated ◽  
High Carrier ◽  
Gas Molecules

The electron mobility of hexadecafluorophthalocyaninato-copper ( F 16 PcCu ) films was evaluated based on field effect measurements in vacuum and in various gas atmospheres. An Arrhenius plot of the mobility showed that the carrier transport followed a thermally activated hopping mechanism with an activation energy of 0.28 eV. The mobility evaluated for freshly prepared films in ultrahigh vacuum was 2.0 × 10−3 cm 2 V −1 s −1 at room temperature. The electrical conductivity and carrier density were 4.4 × 10−5 S cm −1 and 1.4 × 1017 cm −3 respectively. The high carrier density indicated the existence of impurities acting as electron donors in the films. The field effect carrier mobility increased to 5.7 × 10−3 cm 2 V −1 s −1 in NH 3 atmosphere (100%, 1 atm) and decreased by 75% in the presence of O 2 gas (100%, 1 atm). A quick recovery of mobility was observed when the gas molecules were evacuated, indicating a low capability of gas adsorption.

scholarly journals Rational Design of Donor Acceptor Based Semiconducting Copolymers with High Dielectric Constant

2020 ◽  
Author(s):  
Aiswarya Abhisek Mohapatra ◽  
Yifan Dong ◽  
Puttaraju Boregowda ◽  
Ashutosh Mohanty ◽  
Aditya Sadhanala ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Organic Semiconductors ◽  
Density Functional ◽  
Rational Design ◽  
Dielectric Constants ◽  
Side Chains ◽  
Free Charge ◽  
Coulombic Interaction ◽  
Polymer Backbone ◽  
Donor Acceptor

<div> <div> <div> <p>An efficient photogeneration of free charge carriers has long been recognized as the paramount challenge in organic photovoltaic (OPV) devices. The low dielectric constant organic semiconductors fall short to reduce strong Coulombic interaction of tightly bound exciton and hence lead to a loss mechanism in OPVs due to charge-carrier recombination. To circumvent this problem, we adopt a strategy to enhance the dielectric constant of organic semiconductors by incorporating tetraethyleneglycol (TEG) side-chains. We report synthesis of three new semiconducting copolymers by combining thiophene substituted diketopyrrolopyrrole (TDPP) monomer with three other monomeric units with varying electron donating strength: benzodithiophene (BBT-3TEG-TDPP), TDPP (TDPP-3TEG-TDPP) and naphthalene diimide (PNDITEG-TDPP). BBT-3TEG-TDPP and PNDITEG-TDPP showed highest dielectric constants (~ 5) at 1MHz frequency suggesting efficient contribution of dipolar polarization from TEG side-chains. To understand the electronic contribution of the polymer backbone and the polarity of TEG side-chains, and the resulting enhancement of the dielectric constant, we further performed first-principles density functional theory calculations. Single-component organic solar cells (OSC) fabricated utilizing these polymers resulted in poor performance which is attributed to the absence of free charge generation. Furthermore, transient absorption spectroscopy studies show low exciton diffusion length as observed in donor-acceptor type conjugated polymers. Our results suggest that, the strategy of enhancing dielectric constant with polar side-chains is not sufficient to reduce Coulombic interaction between hole and electron in OSCs. </p> </div> </div> </div>

scholarly journals Gated Graphene Electrical Transport Characterization

10.14311/1644 ◽  
2012 ◽  
Vol 52 (5) ◽  
Author(s):  
Josef Náhlík ◽  
Michal Janoušek ◽  
Zbyněk Šobáň
Keyword(s):  
Gate Voltage ◽  
Electrical Transport ◽  
Carrier Mobility ◽  
Room Temperature ◽  
Transparent Material ◽  
Carbon Structure ◽  
Physical Behavior ◽  
Sweep Direction ◽  
New Material ◽  
Higher Carrier Mobility

Graphene is a very interesting new material, and promises attractive applications in future nanodevices. It is a 2D carbon structure with very interesting physical behavior. Graphene is an almost transparent material that has higher carrier mobility than any other material at room temperature. Graphene can therefore be used in applications such as ultrahigh-speed transistors and transparent electrodes. In this paper, we present our preliminary experiments on the transport behavior of graphene at room temperature. We measured the resistivity of Hall-bar samples depending on gate voltage (backgated graphene). Hysteresis between the forward and backward sweep direction was observed.

scholarly journals Evolution of the electronic structure in open-shell donor-acceptor organic semiconductors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhongxin Chen ◽  
Wenqiang Li ◽  
Md Abdus Sabuj ◽  
Yuan Li ◽  
Weiya Zhu ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Organic Semiconductors ◽  
High Performance ◽  
Closed Shell ◽  
Open Shell ◽  
Ground State Structure ◽  
Structure Property ◽  
System A ◽  
Diradical Character ◽  
Donor Acceptor

AbstractMost organic semiconductors have closed-shell electronic structures, however, studies have revealed open-shell character emanating from design paradigms such as narrowing the bandgap and controlling the quinoidal-aromatic resonance of the π-system. A fundamental challenge is understanding and identifying the molecular and electronic basis for the transition from a closed- to open-shell electronic structure and connecting the physicochemical properties with (opto)electronic functionality. Here, we report donor-acceptor organic semiconductors comprised of diketopyrrolopyrrole and naphthobisthiadiazole acceptors and various electron-rich donors commonly utilized in constructing high-performance organic semiconductors. Nuclear magnetic resonance, electron spin resonance, magnetic susceptibility measurements, single-crystal X-ray studies, and computational investigations connect the bandgap, π-extension, structural, and electronic features with the emergence of various degrees of diradical character. This work systematically demonstrates the widespread diradical character in the classical donor-acceptor organic semiconductors and provides distinctive insights into their ground state structure-property relationship.

scholarly journals Understanding the Intrinsic Carrier Transport in Highly Oriented Poly(3-hexylthiophene): Effect of Side Chain Regioregularity

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 815 ◽  
Author(s):  
Sanyin Qu ◽  
Chen Ming ◽  
Qin Yao ◽  
Wanheng Lu ◽  
Kaiyang Zeng ◽  
...  
Keyword(s):  
Transport Properties ◽  
Organic Semiconductors ◽  
High Performance ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Three Dimensional ◽  
Side Chain ◽  
Conductive Atomic Force Microscopy ◽  
Dynamics Simulations ◽  
Carrier Transport Properties

The fundamental understanding of the influence of molecular structure on the carrier transport properties in the field of organic thermoelectrics (OTEs) is a big challenge since the carrier transport behavior in conducting polymers reveals average properties contributed from all carrier transport channels, including those through intra-chain, inter-chain, inter-grain, and hopping between disordered localized sites. Here, combining molecular dynamics simulations and experiments, we investigated the carrier transport properties of doped highly oriented poly(3-hexylthiophene) (P3HT) films with different side-chain regioregularity. It is demonstrated that the substitution of side chains can not only take effect on the carrier transport edge, but also on the dimensionality of the transport paths and as a result, on the carrier mobility. Conductive atomic force microscopy (C-AFM) study as well as temperature-dependent measurements of the electrical conductivity clearly showed ordered local current paths in the regular side chain P3HT films, while random paths prevailed in the irregular sample. Regular side chain substitution can be activated more easily and favors one-dimensional transport along the backbone chain direction, while the irregular sample presents the three-dimensional electron hopping behavior. As a consequence, the regular side chain P3HT samples demonstrated high carrier mobility of 2.9 ± 0.3 cm2/V·s, which is more than one order of magnitude higher than that in irregular side chain P3HT films, resulting in a maximum thermoelectric (TE) power factor of 39.1 ± 2.5 μW/mK2 at room temperature. These findings would formulate design rules for organic semiconductors based on these complex systems, and especially assist in the design of high performance OTE polymers.

scholarly journals New π-Stacking Motifs for Molecular Semiconducting Materials: Bis(bis(8-quinolinyl)amide)metal(II) Complexes of Cr, Mn, Fe, and Zn

2021 ◽  
Author(s):  
Georg Albrecht ◽  
Harald G. Locke ◽  
Pascal Schweitzer ◽  
Jonathan Becker ◽  
Limei Chen ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Organic Semiconductors ◽  
Carrier Transport ◽  
Charge Carrier Transport ◽  
Semiconducting Materials ◽  
Π Stacking ◽  
Organic Complexes ◽  
Metal Organic ◽  
Essential Prerequisite ◽  
Neutral Metal

π-π Stacking of adjacent molecules is an essential prerequisite for charge carrier transport in organic semiconductors. Neutral metal-organic complexes with two pincer-type bis(8-quinolinyl)amide (BQA) ligands forming orthogonal π-systems in complexes...

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