Thermoelectric model to characterize carrier transport in organic semiconductors

It has been shown that light-matter strong coupling of materials can lead to modified and often improved properties which has stimulated considerable interest. While charge transport can be enhanced in n-type organic semiconductors by coupling the electronic transition and thereby splitting the conduction band into polaritonic states, it is not clear whether the same process can also influence carrier transport in the valence band of p-type semiconductors. Here we demonstrate for the first time that it is indeed possible to enhance both the conductivity and photoconductivity of a p-type semiconductor rr-P3HT that is ultra-strongly coupled to plasmonic modes. It is due to the hybrid light-matter character of the virtual polaritonic excitations affecting the linear-response of the material. Furthermore, in addition to being enhanced, the photoconductivity of rr-P3HT shows modified spectral response due to the formation of the hybrid polaritonic states. This illustrates the potential of engineering the vacuum electromagnetic environment to improve the opto-electronic properties of organic materials.

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Structure and Doping Optimization of IDT-Based Copolymers for Thermoelectrics

Polymers ◽

10.3390/polym12071463 ◽

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.

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Carrier Transport in Organic Semiconductors and Insulators

Transport of Information-Carriers in Semiconductors and Nanodevices - Advances in Computer and Electrical Engineering ◽

10.4018/978-1-5225-2312-3.ch011 ◽

2017 ◽

pp. 617-675

Keyword(s):

Organic Semiconductors ◽

Carrier Transport

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Spin Transport and Magneto-Resistance in Organic Semiconductors

MRS Proceedings ◽

10.1557/proc-1154-b10-10 ◽

2009 ◽

Vol 1154 ◽

Author(s):

Mohammad Yunus ◽

P. P. Ruden ◽

Darryl L. Smith

Keyword(s):

Organic Semiconductors ◽

Diffusion Approximation ◽

Carrier Transport ◽

Spin Transport ◽

Spin Injection ◽

Carrier Injection ◽

Drift Diffusion ◽

Spin Currents ◽

Magneto Resistance

AbstractCalculated results for spin injection, transport, and magneto-resistance (MR) in organic semiconductors sandwiched between two ferromagnetic contacts are presented. The carrier transport is modeled by spin dependent device equations in drift-diffusion approximation. In agreement with earlier results, spin injection from ferromagnetic contacts into organic semiconductors can be greatly enhanced if (spin-selective) tunneling is the limiting process for carrier injection. Modeling the tunnel processes with linear contact resistances yields spin currents and MR that tend to increase with increasing bias. We also explore the possibility of bias dependent contact resistances and show that this effect may limit MR to low bias.

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Molecular Requirements for Printable Organic Semiconductors in 7-Alkyl-2-phenyl[1]benzothieno[3,2-b][1]benzothiophenes (Ph-BTBT-Cn’s)

MRS Advances ◽

10.1557/adv.2016.441 ◽

2016 ◽

Vol 1 (38) ◽

pp. 2653-2658

Author(s):

S. Inoue ◽

H. Minemawari ◽

J. Tsutsumi ◽

T. Hamai ◽

S. Arai ◽

...

Keyword(s):

Chain Length ◽

Organic Semiconductors ◽

Field Effect ◽

High Performance ◽

Carrier Transport ◽

Alkyl Chain ◽

Field Effect Transistors ◽

Systematic Investigation ◽

Alkyl Chain Length

ABSTRACTHere we discuss requirements for high performance and solution processable organic semiconductors, by presenting a systematic investigation of 7-alkyl-2-phenyl[1]benzothieno[3,2-b][1]benzothiophenes (Ph-BTBT-Cn’s). We found that the solubility and thermal properties of Ph-BTBT-Cn’s depend systematically on the substituted alkyl-chain length n. The observed features are well understood in terms of the change of molecular packing motif with n: The compounds with n ≤ 4 do not form independent alkyl chain layers, whereas those with n ≥ 5 form isolated alkyl chain layers. The latter compounds afford a series of isomorphous bilayer-type crystal structures that form two-dimensional carrier transport layers within the crystals. We also show that the Ph-BTBT-C10 afford high performance single-crystalline field-effect transistors the mobility of which reaches as high as 15.9 cm2/Vs. These results demonstrate a crucial role of the substituted alkyl chain length for obtaining high performance organic semiconductors and field-effect transistors.

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