Thermoelectric and bulk mobility measurements in pentacene thin films

Kim, Gunho; Shtein, Max; Pipe, Kevin P.

doi:10.1063/1.3556622

Cited by 30 publications

(30 citation statements)

References 28 publications

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“…A clear n-or F-dependence, as previously observed for transport in the a-b plane 12,19 cannot be extracted from this data as variations in l with varying j are in the range of the uncertainty limit of this POEM series.…”

mentioning

confidence: 70%

Hole mobility in thermally evaporated pentacene: Morphological and directional dependence

Günther

Widmer

Kasemann

et al. 2015

Applied Physics Letters

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Pentacene has been extensively studied as an active material for organic field-effect transistors as it shows very good charge carrier mobility along its preferred transport direction. In this contribution, we investigate the hole transport in pentacene thin films by measurement in conventional lateral organic field-effect transistors (OFETs), which yields the hole mobility along the a-b plane of pentacene, and by the recently published potential mapping (POEM) approach, which allows for direct extraction of the charge carrier mobility perpendicular to the substrate, in this case perpendicular to the a-b plane, without the assumption of a specific transport model. While the mobility along the a-b plane—determined from OFET measurements—is found to be in the region of 0.45 cm2/Vs, transport perpendicular to this plane shows an average mobility at least one order of magnitude lower. Investigating also how these effective mobility values depend on the deposition rate of the pentacene films, we find that the decrease in grain size for increasing deposition rate causes the mobility to decrease both parallel and perpendicular to the substrate due to the increased number of grain boundaries to be overcome. For the out-of-plane transport, this effect is found to saturate for deposition rates higher than 2.5 Å/s.

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mentioning

confidence: 70%

Hole mobility in thermally evaporated pentacene: Morphological and directional dependence

Günther

Widmer

Kasemann

et al. 2015

Applied Physics Letters

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“…The smaller S value than that of the F 4 TCNQ‐doped samples was caused by higher carrier concentration in this case. The disadvantage of such iodine‐doped thin films of pentacene is the poor stability . K. Hayashi et al .…”

Section: Organic Thermoelectric Materials Based On Small Moleculesmentioning

confidence: 99%

“…Since the dawn of the 21st century there have been ongoing efforts to employ organic materials especially conductive polymers as thermoelectric materials . Meanwhile, small conjugated molecules like pentacene and fullerene (C 60 ) have been doped and used as p‐ and n‐ type TEG legs respectively. After incubation over a decade, the highest ZT values achieved to date are respectively 0.42 and 0.20 for p‐ and n‐ type organic thermoelectric materials.…”

Section: Introductionmentioning

confidence: 99%

Organic Thermoelectric Materials: Emerging Green Energy Materials Converting Heat to Electricity Directly and Efficiently

et al. 2014

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The abundance of solar thermal energy and the widespread demands for waste heat recovery make thermoelectric generators (TEGs) very attractive in harvesting low-cost energy resources. Meanwhile, thermoelectric refrigeration is promising for local cooling and niche applications. In this context there is currently a growing interest in developing organic thermoelectric materials which are flexible, cost-effective, eco-friendly and potentially energy-efficient. In particular, the past several years have witnessed remarkable progress in organic thermoelectric materials and devices. In this review, thermoelectric properties of conducting polymers and small molecules are summarized, with recent progresses in materials, measurements and devices highlighted. Prospects and suggestions for future research efforts are also presented. The organic thermoelectric materials are emerging candidates for green energy conversion.

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“…To alter the carrier concentration in organic materials, chemical doping is commonly used, but it is difficult to continuously tuning the doping level. [181,182] Alternatively, the channel carrier concentration in an OFET can be easily tuned by varying the gate voltage, providing a feasible way to examine the carrier concentration dependent on the Seebeck coefficient. This could accelerate the study of organic thermoelectric materials, and recent developments in this regard will be introduced in the following.…”

Section: Thermoelectric Figure Of Meritsmentioning

confidence: 99%

Organic Field‐Effect Transistor for Energy‐Related Applications: Low‐Power‐Consumption Devices, Near‐Infrared Phototransistors, and Organic Thermoelectric Devices

Ren

Yang

Gao

et al. 2018

Advanced Energy Materials

106

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The operating frequency of ring oscillators or radio-frequency identification tags made by OFETs have surpassed MHz. [27,28] With the growing level of integration and the operating frequency of OFETs, the power dissipation issue can no longer be ignored. Considering the material composition of most organic semiconductors, controlling the temperature rise within a reasonable range is important to avoid the unwanted degradation of organic materials and therefore maintain stable device operation. In addition, OFETs fabricated on flexi ble substrates somehow limit the use of conventional batteries. To avoid externally wiring the batteries, flexible OFET-based circuits can be expected to be self-powered by integrating them with organic solar cells, thermoelectric modules, or triboelectric nanogenerators. [29,30] All of these demands require OFETs operating with extremely low power consumption. Rapid progress has been made in this field, and research efforts have focused on reducing the operating voltage of OFETs, [31][32][33] enhancing the switching efficiency of transistors, [34][35][36][37] and demonstrating several novel device concepts for low-power applications. [38][39][40][41][42] Despite the switching function, OFETs can also be utilized in emerging energy-related applications, such as near-infrared (NIR) photodetectors and organic thermoelectric devices dueThe organic field-effect transistor (OFET) is the basic building block of integrated circuits. The charge carrier mobility and operating frequency of OFETs have continued to increase; therefore, the power dissipation of OFETs can no longer be ignored. Many research efforts have been made to develop low-power-consumption OFETs and complementary circuits. Despite the switching function, OFETs can also be utilized in emerging energy-related applications, such as near-infrared (NIR) photodetectors and organic thermoelectric devices. Organic phototransistors show considerably higher photo responsivity than other photodetector architectures due to field-effect charge modulation. The photoinduced gate modulating largely suppresses the dark current while simultaneously providing gain. These characteristics may favor NIR light detection and suggest that the organic phototransistor is a promising candidate for optoelectronic applications in the NIR regime. For organic thermoelectric applications, OFETs can work as a powerful tool for examining the charge and energy transport in the organic semiconductor, thus giving insight into organic thermoelectric studies. In this review, the authors highlight recent advances in OFET-related energy topics, including lowpower-consumption OFETs, NIR photodetectors, and organic thermoelectric devices. The remaining challenges in the field will also be discussed.

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Thermoelectric and bulk mobility measurements in pentacene thin films

Cited by 30 publications

References 28 publications

Hole mobility in thermally evaporated pentacene: Morphological and directional dependence

Hole mobility in thermally evaporated pentacene: Morphological and directional dependence

Organic Thermoelectric Materials: Emerging Green Energy Materials Converting Heat to Electricity Directly and Efficiently

Organic Field‐Effect Transistor for Energy‐Related Applications: Low‐Power‐Consumption Devices, Near‐Infrared Phototransistors, and Organic Thermoelectric Devices

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