Thermal diffusivities of functionalized pentacene semiconductors

Zhang, H.; Yao, Yulong; Payne, Marcia M.; Anthony, John E.; Brill, J. W.

doi:10.1063/1.4894094

Cited by 17 publications

(30 citation statements)

References 26 publications

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“…The difference between and el may be attributed to the heat carried by phonons accounting for a rather temperature-independent contribution of ph ≈ 2.1 W/(m K). Similar values of 1.6 W/(m K) in semiconducting, needle-like crystals of functionalized pentacenes have been determined along the stacking direction [27] . The large 7 apparent ph may also point to an increased as predicted and experimentally verified for quasi-onedimensional Luttinger liquids [10,28] .…”

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Low‐Cost and Sustainable Organic Thermoelectrics Based on Low‐Dimensional Molecular Metals

et al. 2017

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk 1 DOI: 10.1002/((please add manuscript number)) Article type: Communication Low-Cost and Sustainable Organic Thermoelectrics Based on LowDimensional Molecular MetalsBy Florian Huewe*, Alexander Steeger*, Kalina Kostova, Laurence Burroughs, Irene Bauer, Peter Strohriegl, Vladimir Dimitrov, Simon Woodward and Jens Pflaum* F. Huewe [ †] , A. Steeger [ †] The dimensionless figure of merit measures a material's thermoelectric performancewhere electrical conductivity (resistivity ), Seebeck coefficient/thermopower , and thermal conductivity provide the power factor = 2 . Materials with high electrical conductivity and thermopower but low thermal conductivity are desirable to maximize and hence, the thermoelectric conversion efficiency. Approximately, is inversely proportional to which in turn is related to the electronic thermal conductivity el = via the Wiedemann-Franz (WF) law.Advances in have been achieved by tuning the doping of semiconductors to maximize the [6] together with reducing the phononic contribution to thermal conduction by means of nanostructured superlattice architectures [7,8] . To overcome the inherent limitations of ordinary materials, a dimensionality reduction of the electronic system has been proposed [9] . This can lead to a violation of the WF law [10,11] and to phonon drag contributions to the thermopower [12] . Complex crystal structures, e.g. Zintl compounds [13] and skutterudites [14] , have been evaluated as good thermoelectric 3 candidates due to reduced lattice thermal conductivity and electronic band structure tunability. These optimization strategies, together with the ability for low-cost production and low-temperature processibility, have recently raised interest in organic polymers [15] , such as PEDOT:Tos, reaching = 0.25 at room temperature (RT) [4] and thus advancing the value of = 1.2 obtained for Bi2Te3 (the best RT thermoelectric material to date [7] ). Herein, quasi-1D organic conductors based on small molecules constitute a new, sustainable approach towards organic thermoelectrics that provide many of the desired electrical and thermal properties described above. Additionally, they are lightweight and thermodynamically stable allowing for portable device manufacturing and long-term usage. In comparison to organic polymers the availability of electrically high-performing p-and ntype organic conductors facilitates the construction of all-organic thermoelectric devices.As a starting point we chose two of the best p-and n-type conducting radical ion salts, TTT2I3 (TTT = Tetrathiotetracene) and (DMe-DCNQI)2Cu (DMe-DCNQI = Dimethyl-Dicyanoquinonediimine).They form macroscopic needle-like sin...

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Low‐Cost and Sustainable Organic Thermoelectrics Based on Low‐Dimensional Molecular Metals

et al. 2017

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“…This value of κ, similar to that of polymers, [18][19][20] is an order of magnitude smaller than the in-plane (needle axis) thermal conductivity 4 and two orders of magnitude smaller than the caxis 5 thermal conductivity of crystals. Similarly, for diF-TES-ADT, the average value of R film /t gives κ = (0.135 ± 0.015) W/m⋅K, almost two orders of magnitude smaller than the c-axis value for TES-ADT, with a very similar structure.…”

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confidence: 60%

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6] For molecules with planar backbones and silylethynyl (or germanylethynyl) sidegroups projecting between planes, very high interplanar thermal conductivities have been observed. 4,5 For example, while the in-plane, "needle-axis" (i.e. the direction of crystal growth and highest electronic conductivity) thermal conductivity of bis(triisopropylsilylethynyl) pentacene (TIPS-pn [7][8][9][10] ) κ needle ≈ 1.6 W/m⋅K, 4 the inter-plane (caxis) thermal conductivity has been measured, using an ac-photothermal technique, 5 to be κ c ≈ 21 W/m⋅K, a value close to that of sapphire.…”

Section: Introductionmentioning

confidence: 99%

“…4,5 For example, while the in-plane, "needle-axis" (i.e. the direction of crystal growth and highest electronic conductivity) thermal conductivity of bis(triisopropylsilylethynyl) pentacene (TIPS-pn [7][8][9][10] ) κ needle ≈ 1.6 W/m⋅K, 4 the inter-plane (caxis) thermal conductivity has been measured, using an ac-photothermal technique, 5 to be κ c ≈ 21 W/m⋅K, a value close to that of sapphire. 11 As discussed below, this large value and inverted anisotropy (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Thermal resistances of thin films of small molecule organic semiconductors

et al. 2016

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Abstract:We have measured the thermal resistances of thin films of the small molecule organic semiconductors bis(triisopropylsilylethynyl) pentacene (TIPS-pn), bis(triethylsilylethynyl) anthradithiophene (TES-ADT) and difluoro bis(triethylsilylethynyl) anthradithiophene (diF-TES-ADT). For each material, several films of different thicknesses have been measured to separate the effects of intrinsic thermal conductivity from interface thermal resistance. For sublimed films of TIPS-pn and diF-TES-ADT, with thicknesses ranging from < 100 nm to > 4 µm, the thermal conductivities are similar to that of polymers and over an order of magnitude smaller than that of single crystals, presumably reflecting the large reduction in phonon mean-free path in the films. For thin (≤ 205 nm) crystalline films of TES-ADT, prepared by vapor-annealing spin-cast films, the thermal resistances are dominated by interface scattering.

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Boosting Direct X‐Ray Detection in Organic Thin Films by Small Molecules Tailoring

Ciavatti

Basiricò

Fratelli

et al. 2018

Adv Funct Materials

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The attention on the application of organic electronics for the detection of ionizing radiation is rapidly growing among the international scientific community, due to the great potential of the organic technology to enable large-area conformable sensor panels. However, high-energy photon absorption is challenging as organic materials are constituted of atoms with low atomic numbers.Here it is reported how, by synthesizing new solution-processable organic molecules derived from 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) and 2,8-Difluoro-5,11bis(triethylsilylethynyl)anthradithiophene (diF-TES-ADT), with Ge-substitution in place of the Si atoms to increase the material atomic number, it is possible to boost the X-ray detection performance of organic thin films on flexible plastic substrates. TIPGe-pentacene based flexibleOTFTs show high electrical performance with higher mobility (0.4 cm 2 V -1 s -1 ) and enhanced X-ray sensitivity, up to 9.0 x 10 5 µC Gy -1 cm -3 , with respect to TIPS-pentacene based detectors. Moreover, similar results are obtained for diF-TEG-ADT devices, confirming that the proposed strategy, i.e.increasing the atomic number of organic molecules by chemical tailoring to improve X-ray sensitivity, can be generalized to organic thin film detectors, combining high X-ray absorption, mechanical flexibility and large area processing.

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Thermal diffusivities of functionalized pentacene semiconductors

Cited by 17 publications

References 26 publications

Low‐Cost and Sustainable Organic Thermoelectrics Based on Low‐Dimensional Molecular Metals

Low‐Cost and Sustainable Organic Thermoelectrics Based on Low‐Dimensional Molecular Metals

Thermal resistances of thin films of small molecule organic semiconductors

Boosting Direct X‐Ray Detection in Organic Thin Films by Small Molecules Tailoring

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