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Ullah Khan, Zia
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Publications (10 of 15) Show all publications
Zhao, D., Martinelli, A., Willfahrt, A., Fischer, T., Bernin, D., Ullah Khan, Z., . . . Crispin, X. (2019). Polymer gels with tunable ionic Seebeck coefficient for ultra-sensitive printed thermopiles. Nature Communications, 10, Article ID 1093.
Open this publication in new window or tab >>Polymer gels with tunable ionic Seebeck coefficient for ultra-sensitive printed thermopiles
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2019 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, article id 1093Article in journal (Refereed) Published
Abstract [en]

Measuring temperature and heat flux is important for regulating any physical, chemical, and biological processes. Traditional thermopiles can provide accurate and stable temperature reading but they are based on brittle inorganic materials with low Seebeck coefficient, and are difficult to manufacture over large areas. Recently, polymer electrolytes have been proposed for thermoelectric applications because of their giant ionic Seebeck coefficient, high flexibility and ease of manufacturing. However, the materials reported to date have positive Seebeck coefficients, hampering the design of ultra-sensitive ionic thermopiles. Here we report an “ambipolar” ionic polymer gel with giant negative ionic Seebeck coefficient. The latter can be tuned from negative to positive by adjusting the gel composition. We show that the ion-polymer matrix interaction is crucial to control the sign and magnitude of the ionic Seebeck coefficient. The ambipolar gel can be easily screen printed, enabling large-area device manufacturing at low cost.

Place, publisher, year, edition, pages
Nature Publishing Group, 2019
Keywords
Ionic Thermopiles; thermoelectric; screen printing; ionic liquid
National Category
Other Physics Topics
Identifiers
urn:nbn:se:liu:diva-154943 (URN)10.1038/s41467-019-08930-7 (DOI)000460410800001 ()30842422 (PubMedID)
Note

Funding agencies:  Swedish research council [2016-03979, 2015-05070]; Swedish Governmental Agency for Innovation Systems [2015-04859]; Advanced Functional Materials Center at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; United States National Science Found

Available from: 2019-03-06 Created: 2019-03-06 Last updated: 2019-03-26Bibliographically approved
Malti, A., Edberg, J., Granberg, H., Ullah Khan, Z., Andreasen, J. W., Liu, X., . . . Berggren, M. (2016). An Organic Mixed Ion–Electron Conductor for Power Electronics. Advanced Science, Article ID 1500305.
Open this publication in new window or tab >>An Organic Mixed Ion–Electron Conductor for Power Electronics
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2016 (English)In: Advanced Science, ISSN 2198-3844, article id 1500305Article in journal (Refereed) Published
Abstract [en]

A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting nanopaper are exploited in devices which exhibit record values for the charge storage capacitance (1F) in supercapacitors and transconductance (1S) in electrochemical transistors.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2016
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-123225 (URN)10.1002/advs.201500305 (DOI)000370336500011 ()
Note

Funding agencies:  Knut and Alice Wallenberg foundation [KAW 2011.0050]; Onnesjo Foundation; Advanced Functional Materials Center at Linkoping University; Stiftelsen for strategisk forskning (SSF); RISE Research Institutes of Sweden; U.S. National Science Foundation [DMR-12

Available from: 2015-12-08 Created: 2015-12-08 Last updated: 2018-02-15
Zhao, D., Wang, H., Ullah Khan, Z., Chen, J. C., Gabrielsson, R., Jonsson, M., . . . Crispin, X. (2016). Ionic thermoelectric supercapacitors. Energy & Environmental Science, 9(4), 1450-1457
Open this publication in new window or tab >>Ionic thermoelectric supercapacitors
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2016 (English)In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 9, no 4, p. 1450-1457Article in journal (Refereed) Published
Abstract [en]

Temperature gradients are generated by the sun and a vast array of technologies and can induce molecular concentration gradients in solutions via thermodiffusion (Soret effect). For ions, this leads to a thermovoltage that is determined by the thermal gradient Delta T across the electrolyte, together with the ionic Seebeck coefficient alpha(i). So far, redox-free electrolytes have been poorly explored in thermoelectric applications due to a lack of strategies to harvest the energy from the Soret effect. Here, we report the conversion of heat into stored charge via a remarkably strong ionic Soret effect in a polymeric electrolyte (Seebeck coefficients as high as alpha(i) = 10 mV K-1). The ionic thermoelectric supercapacitor (ITESC) is charged under a temperature gradient. After the temperature gradient is removed, the stored electrical energy can be delivered to an external circuit. This new means to harvest energy is particularly suitable for intermittent heat sources like the sun. We show that the stored electrical energy of the ITESC is proportional to (Delta T alpha(i))(2). The resulting ITESC can convert and store several thousand times more energy compared with a traditional thermoelectric generator connected in series with a supercapacitor.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2016
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-128769 (URN)10.1039/c6ee00121a (DOI)000374351200029 ()
Note

Funding Agencies|European Research Council (ERC) [307596]; Swedish foundation for strategic research (SSF); Knut and Alice Wallenberg foundation (KAW); Swedish Energy Agency; Wenner-Gren Foundations; Advanced Functional Materials Centre at Linkoping University.

The previous status of this article was Manuscript.

Available from: 2016-05-30 Created: 2016-05-30 Last updated: 2018-08-31Bibliographically approved
Ullah Khan, Z., Edberg, J., Max Hamedi, M., Gabrielsson, R., Granberg, H., Wågberg, L., . . . Crispin, X. (2016). Thermoelectric Polymers and their Elastic Aerogels. Advanced Materials, 28(22), 4556-4562
Open this publication in new window or tab >>Thermoelectric Polymers and their Elastic Aerogels
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2016 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 28, no 22, p. 4556-4562Article in journal (Refereed) Published
Abstract [en]

Electronically conducting polymers constitute an emerging class of materials for novel electronics, such as printed electronics and flexible electronics. Their properties have been further diversified to introduce elasticity, which has opened new possibility for "stretchable" electronics. Recent discoveries demonstrate that conducting polymers have thermoelectric properties with a low thermal conductivity, as well as tunable Seebeck coefficients - which is achieved by modulating their electrical conductivity via simple redox reactions. Using these thermoelectric properties, all-organic flexible thermoelectric devices, such as temperature sensors, heat flux sensors, and thermoelectric generators, are being developed. In this article we discuss the combination of the two emerging fields: stretchable electronics and polymer thermoelectrics. The combination of elastic and thermoelectric properties seems to be unique for conducting polymers, and difficult to achieve with inorganic thermoelectric materials. We introduce the basic concepts, and state of the art knowledge, about the thermoelectric properties of conducting polymers, and illustrate the use of elastic thermoelectric conducting polymer aerogels that could be employed as temperature and pressure sensors in an electronic-skin.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2016
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:liu:diva-129660 (URN)10.1002/adma.201505364 (DOI)000377123500029 ()26836440 (PubMedID)
Note

Funding Agencies|European Research Council (ERC) [307596]; Swedish Foundation for Strategic Research; Knut and Alice Wallenberg Foundation; Swedish Energy Agency; Advanced Functional Materials Center at Linkoping University; Research Institute of Sweden (RISE)

Available from: 2016-06-27 Created: 2016-06-23 Last updated: 2018-09-07
Ullah Khan, Z., Bubnova, O., Jafari, M. J., Brooke, R., Liu, X., Gabrielsson, R., . . . Crispin, X. (2015). Acido-basic control of the thermoelectric properties of poly(3,4-ethylenedioxythiophene)tosylate (PEDOT-Tos) thin films. Journal of Materials Chemistry C, 3, 10616-10623
Open this publication in new window or tab >>Acido-basic control of the thermoelectric properties of poly(3,4-ethylenedioxythiophene)tosylate (PEDOT-Tos) thin films
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2015 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 3, p. 10616-10623Article in journal (Refereed) Published
Abstract [en]

PEDOT-Tos is one of the conducting polymers that displays the most promising thermoelectric properties. Until now, it has been utterly difficult to control all the synthesis parameters and the morphology governing the thermoelectric properties. To improve our understanding of this material, we study the variation in the thermoelectric properties by a simple acido-basic treatment. The emphasis of this study is to elucidate the chemical changes induced by acid (HCl) or base (NaOH) treatment in PEDOT-Tos thin films using various spectroscopic and structural techniques. We could identify changes in the nanoscale morphology due to anion exchange between tosylate and Cl- or OH-. But, we identified that changing the pH leads to a tuning of the oxidation level of the polymer, which can explain the changes in thermoelectric properties. Hence, a simple acid-base treatment allows finding the optimum for the power factor in PEDOT-Tos thin films.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2015
National Category
Polymer Chemistry Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:liu:diva-121977 (URN)10.1039/C5TC01952D (DOI)000363251600035 ()
Note

Funding agencies: European Research Council (ERC) [307596]

Available from: 2015-10-14 Created: 2015-10-14 Last updated: 2018-08-20Bibliographically approved
Malti, A., Edberg, J., Granberg, H., Khan, Z. U., Andreasen, J. W., Liu, X., . . . Berggren, M. (2015). Enabling organic power electronics with a cellulose nano-scaffold.
Open this publication in new window or tab >>Enabling organic power electronics with a cellulose nano-scaffold
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2015 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Exploiting the nanoscale properties of certain materials enables the creation of new materials with a unique set of properties. Here, we report on an electronic (and ionic) conducting paper based on cellulose nanofibrils (CNF) composited with poly(3,4-ethylene-dioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS), which may be facilely processed into large three-dimensional geometries, while keeping unprecedented electronic and ionic conductivities of 140 S/cm and 20 mS/cm, respectively. This is achieved by cladding the CNF with PEDOT:PSS, and trapping an ion-transporting phase in the interstices between these nanofibrils. The unique properties of the resulting nanopaper composite have been used to demonstrate (electrochemical) transistors, supercapacitors and conductors resulting in exceptionally high device parameters, such as an associated transconductance, charge storage capacity and current level beyond 1 S, 1 F and 1 A, respectively.

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-122021 (URN)
Available from: 2015-10-16 Created: 2015-10-16 Last updated: 2018-02-15Bibliographically approved
Wang, H., Khan, Z. U., Zhao, D., Berggren, M. & Crispin, X. (2015). Ionic Thermoelectric effect in Polyelectrolytes.
Open this publication in new window or tab >>Ionic Thermoelectric effect in Polyelectrolytes
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2015 (English)Manuscript (preprint) (Other academic)
National Category
Physical Sciences Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-121980 (URN)
Available from: 2015-10-14 Created: 2015-10-14 Last updated: 2017-02-03Bibliographically approved
Khan, Z. U., Edberg, J., Hamedi, M., Gabrielsson, R., Granberg, H., Engquist, I., . . . Crispin, X. (2015). Nanofibrillated cellulose aerogels functionalized with conducting polymers for thermoelectric and dual-sensing applications.
Open this publication in new window or tab >>Nanofibrillated cellulose aerogels functionalized with conducting polymers for thermoelectric and dual-sensing applications
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2015 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Large amount of heat is wasted in industries, power generation plants and ordinary household appliances. This waste heat, can be a useful input to a thermoelectric generator (TEG) that can convert it to electricity. Conducting polymers (CPs) have been proved as best suited thermoelectric (TE) materials for lower temperatures, being not toxic, abundant in nature and solution processible. So far, CPs have been characterized as thin films, but it needs the third dimension to realize vertical TEGs which is possible by coating it on low thermal conductivity 3D skeletons. In this work, porous bulk cellulose structures have been used as a supporting material and were coated with CPs in various ways. The blend of cellulose and polymer were also freeze-dried, resulting in conducting and soft composites. Those flexible aerogels were utilized as a dual parameter sensor to sense pressure and temperature, based on the concept of thermoelectricity. It opens another application area of sensing, utilizing the thermoelectric phenomenon beyond the prevailing power generation concept. The sensitivity of such materials can be enhanced to make them useful as electronic skin in healthcare and robotics.

National Category
Physical Sciences Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-121981 (URN)
Available from: 2015-10-14 Created: 2015-10-14 Last updated: 2018-02-15Bibliographically approved
Weathers, A., Ullah Khan, Z., Brooke, R., Evans, D., Pettes, M. T., Wenzel Andreasen, J., . . . Shi, L. (2015). Significant Electronic Thermal Transport in the Conducting Polymer Poly(3,4-ethylenedioxythiophene). Advanced Materials, 27(12), 2101-2106
Open this publication in new window or tab >>Significant Electronic Thermal Transport in the Conducting Polymer Poly(3,4-ethylenedioxythiophene)
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2015 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 27, no 12, p. 2101-2106Article in journal (Refereed) Published
Abstract [en]

Suspended microdevices are employed to measure the in-plane electrical conductivity, thermal conductivity, and Seebeck coefficient of suspended poly(3,4-ethylenedioxythiophene) (PEDOT) thin films. The measured thermal conductivity is higher than previously reported for PEDOT and generally increases with the electrical conductivity. The increase exceeds that predicted by the Wiedemann-Franz law for metals and can be explained by significant electronic thermal transport in PEDOT.

Place, publisher, year, edition, pages
Wiley-VCH Verlag, 2015
Keywords
conducting polymers; poly(3, 4-ethylenedioxythiophene); thermal conductivity; thermoelectric materials; Wiedemann-Franz law
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-117379 (URN)10.1002/adma.201404738 (DOI)000351681300018 ()25688732 (PubMedID)
Note

Funding Agencies|US National Science Foundation Thermal Transport Processes Program [CBET-0933454]; European Research Council (ERC) [307596]; Swedish foundation for strategic research; Knut and Alice Wallenberg foundation; Swedish Energy Agency; NSF Graduate Research Fellowship Program

Available from: 2015-04-24 Created: 2015-04-24 Last updated: 2017-12-04
Mitraka, E., Kergoat, L., Ullah Khan, Z., Fabiano, S., Douheret, O., Leclere, P., . . . Crispin, X. (2015). Solution processed liquid metal-conducting polymer hybrid thin films as electrochemical pH-threshold indicators. Journal of Materials Chemistry C, 3(29), 7604-7611
Open this publication in new window or tab >>Solution processed liquid metal-conducting polymer hybrid thin films as electrochemical pH-threshold indicators
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2015 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 3, no 29, p. 7604-7611Article in journal (Refereed) Published
Abstract [en]

A global and accurate mapping of the environment could be achieved if sensors and indicators are mass-produced at low cost. Printed electronics using polymeric (semi) conductors offer a platform for such sensor/indicator based circuits. Herein, we present the material concept for an electrochemical pH-threshold indicator based on a printable hybrid electrode which comprises a liquid metal alloy (GaInSn) embedded in a conducting polymer matrix (PEDOT). This hybrid electrode displays a large variation in open circuit potential versus pH in an electrochemical cell, which when connected to the gate of an electrochemical transistor leads to a dramatic change in the drain current in a narrow range of pH.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2015
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-120667 (URN)10.1039/c5tc00753d (DOI)000358228400010 ()
Note

Funding Agencies|European Research Council (ERC-starting-grant) [307596]; European Commission; Region Wallonne (FEDER Revetements Fonctionnels program) [475225-579695]; BELSPO [IAP 7/05]; OPTI2MAT Excellence program of Region Wallonne [816925]; FNRS-FRFC

Available from: 2015-08-20 Created: 2015-08-20 Last updated: 2018-08-20
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