liu.seSearch for publications in DiVA
Change search
Link to record
Permanent link

Direct link
BETA
Said, Elias
Publications (9 of 9) Show all publications
Said, E., Andersson, P., Engquist, I., Crispin, X. & Berggren, M. (2009). Electrochromic display cells driven by an electrolyte-gated organic field-effect transistor. Organic electronics, 10(6), 1195-1199
Open this publication in new window or tab >>Electrochromic display cells driven by an electrolyte-gated organic field-effect transistor
Show others...
2009 (English)In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 10, no 6, p. 1195-1199Article in journal (Refereed) Published
Abstract [en]

Monolithic integration of an electrolyte-gated organic field-effect transistor (OFET) and an organic electrochromic pixel is reported. Thanks to its versatility, the polyanionic proton conductor poly(styrenesulfonic acid) (PSSH) can serve both as the gate “insulator” in OFETs and as the electrolyte in electrochromic display pixels. Employing identical materials in both the display cells and in the driver transistors is a necessary prerequisite to achieve robust displays possible to manufacture on flexible carriers using printing tools. Smart pixels combining depletion mode electrochemical transistors and electrochromic displays have been reported in the past. Here, an enhancement mode OFET as the driver enables relatively shorter updating times and much simpler addressing and updating schemes.

Keywords
Organic field-effect transistor (OFET); Electrolyte-gated OFET; Electrochromic display; Active matrix display; Smart pixel
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-15728 (URN)10.1016/j.orgel.2009.06.008 (DOI)
Available from: 2008-12-04 Created: 2008-12-01 Last updated: 2017-12-14Bibliographically approved
Said, E. (2009). Electrolyte: Semiconductor Combinations for Organic Electronic Devices. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Electrolyte: Semiconductor Combinations for Organic Electronic Devices
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The discovery of semi-conducting organic materials has opened new possibilities for electronic devices and systems because of their solution processibility, lightweight and flexibility compared to inorganic semiconductors. The combination of semiconductors with electrolytes, and more especially organic semiconductors and solid electrolytes has attracted the attention of researchers because of the multiple phenomena originating from the simultaneous motion of electrons and ions.

This thesis deals with organic-based devices whose working mechanism involves electrolytes. By measuring electrochromism induced by the field in isolated segments of conjugated polymer films, which is in contact with an electrolyte, the direction and the magnitude of the electric field along an electrolyte is quantified (paper I). In addition, using a polyanionic proton conductor in organic field-effect transistor (OFET) as gate dielectric results in low operation voltage and fast response thanks to the high capacitance of the electric double layer (EDLC) that is formed at organic semiconductor/ polyelectrolyte interface (paper III). Because an electrolyte is used as a gate insulator, the effect of the ionic currents on the performance of an EDLC-OFET has been investigated by varying the relative humidity of the device ambience (paper IV). Since the EDLC-OFET and the electrochromic display cell both are operated at low voltages, the transistor has been monolithically integrated with an electrochromic pixel, i.e. combining a solid state device and an electrochemical device (paper V). Further, a theoretical study of the electrostatic potential within a so called pen-heterojunction made up of two semi-infinite, doped semiconductor media separated by an electrolyte region is reported (paper II).

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2009. p. 58
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1228
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-15775 (URN)978-91-7393-735-1 (ISBN)
Public defence
2009-01-09, TP2, Täppan, Campus Norrköping, Linköpings universitet, Norrköping, 10:15 (English)
Opponent
Supervisors
Available from: 2008-12-03 Created: 2008-12-03 Last updated: 2020-02-19Bibliographically approved
Larsson, O., Said, E., Berggren, M. & Crispin, X. (2009). Insulator Polarization Mechanisms in Polyelectrolyte-Gated Organic Field-Effect Transistors. Advanced Functional Materials, 19(20), 3334-3341
Open this publication in new window or tab >>Insulator Polarization Mechanisms in Polyelectrolyte-Gated Organic Field-Effect Transistors
2009 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 19, no 20, p. 3334-3341Article in journal (Refereed) Published
Abstract [en]

Electrolyte-gated organic field-effect transistors (OFETs) hold promise for robust printed electronics operating at low voltages. The polarization mechanism of thin solid electrolyte films, the gate insulator in such OFETs, is still unclear and appears to limit the transient current characteristics of the transistors. Here, the polarization response of a thin proton membrane, a poly(styrenesulfonic acid) film, is controlled by varying the relative humidity. The formation of the conducting transistor channel follows the polarization of the polyelectrolyte, such that the drain transient current characteristics versus the time are rationalized by three different polarization mechanisms: the dipolar relaxation at high frequencies, the ionic relaxation (migration) at intermediate frequencies, and the electric double-layer formation at the polyelectrolyte interfaces at low frequencies. The electric double layers of polyelectrolyte capacitors are formed in 1 µs at humid conditions and an effective capacitance per area of 10 µF cm-2 is obtained at 1 MHz, thus suggesting that this class of OFETs might operate at up to 1 MHz at 1 V.

Place, publisher, year, edition, pages
Wiley InterScience, 2009
Keywords
Dielectrics, Ionic conductivity, Organic electronics, Organic field-effect transistors, Polyelectrolytes
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-51545 (URN)10.1002/adfm.200900588 (DOI)
Available from: 2009-11-05 Created: 2009-11-05 Last updated: 2017-12-12Bibliographically approved
Said, E., Larsson, O., Berggren, M. & Crispin, X. (2008). Effects of the Ioinc Currents in Electrolyte-gated Organic Field-Effect Transistors. Advanced Functional Materials, 18(21), 3529-3536
Open this publication in new window or tab >>Effects of the Ioinc Currents in Electrolyte-gated Organic Field-Effect Transistors
2008 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 18, no 21, p. 3529-3536Article in journal (Refereed) Published
Abstract [en]

Polyelectrolytes are promising materials as gate dielectrics in organic field-effect transistors (OFETs). Upon gate bias, their polarization induces an ionic charging current, which generates a large double layer capacitor (10-500 µF cm-2) at the semiconductor/electrolyte interface. The resulting transistor operates at low voltages (<1 V) and its conducting channel is formed in 50 µs. The effect of ionic currents on the performance of the OFETs is investigated by varying the relative humidity of the device ambience. Within defined humidity levels and potential values, the water electrolysis is negligible and the OFETs performances are optimum.

Place, publisher, year, edition, pages
Weinheim: WILEY-VCH Verlag GmbH & Co. KGaA, 2008
Keywords
electrolytes, field-effect transistors, ionic conductivity, organic electronics
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-15724 (URN)10.1002/adfm.200701251 (DOI)
Available from: 2008-12-04 Created: 2008-12-01 Last updated: 2017-12-14Bibliographically approved
Said, E. (2007). Electrolyte-Based Organic Electronic Devices. (Licentiate dissertation). : Institutionen för teknik och naturvetenskap
Open this publication in new window or tab >>Electrolyte-Based Organic Electronic Devices
2007 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The discovery of semi-conducting and conducting organic materials has opened new possibilities for electronic devices and systems. Applications, previously unattainable for conventional electronics, have become possible thanks to the development of conjugated polymers. Conjugated polymers that are both ion- and electron conducting, allow for electrochemical doping and de-doping via reversible processes as long as both forms of conduction remain available. Doping causes rearrangement of the -system along the polymer backbone, and creates new states in the optical band gap, resulting in an increased electronic conductivity and also control of the color (electrochromism). Doping can also occur by charge injection at a metal – semiconducting polymer interface. Electrochemical electronic devices and solid state devices based on these two types of doping are now beginning to enter the market.

This thesis deals with organic based-devices whose working mechanism involves electrolytes. After describing the properties of conjugated polymers, fundamentals on electrolytes (ionic conductivity, types, electric double layer and the electric field distribution) are briefly presented. Thereafter, a short review of the field of organic field effect transistors as well as a description of transistors that are gated via an electrolyte will be reviewed.

Paper I present a novel technique to visualize the electric field within a two-dimensional electrolyte by applying the electrolyte over an array of electronically isolated islands of electrochromic polymer material on a plastic foil. By observing the color change within each polymer island the direction and the magnitude of the electric field can be measured. This technology has applications in electrolyte evaluation and is also applicable in bio-analytical measurements, including electrophoresis. The focus of paper II lies on gating an organic field effect transistor (OFET) by a polyanionic proton conductor. The large capacitance of the electric double layer (EDL) that is formed at organic semiconductor/polyelectrolyte upon applying a potential to the gate, results in low operation voltages and fast response. This type of transistor that is gated via electric double layer capacitor is called EDLC-OFET. Because an electrolyte is used as a gate insulator, the role of the ionic conductivity of the electrolyte is considered in paper III. The effect on the electronic performance of the transistor is studied as well by varying the humidity level.

Place, publisher, year, edition, pages
Institutionen för teknik och naturvetenskap, 2007. p. 38
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1330
Keywords
Conjugated polymers, Electrolytes, Organic Field Effect Transistors
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-9955 (URN)978-91-85895-90-8 (ISBN)
Presentation
2007-09-28, TP2, Täppan, Campus Norrköping, Linköpings universitet, Norrköping, 10:15 (English)
Opponent
Supervisors
Available from: 2007-10-12 Created: 2007-10-12 Last updated: 2017-02-03
Miklavcic, S. J. & Said, E. (2006). Electrostatic potential and double layer force in a semiconductor-electrolyte-semiconductor heterojunction. Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, 74(6), 061606-
Open this publication in new window or tab >>Electrostatic potential and double layer force in a semiconductor-electrolyte-semiconductor heterojunction
2006 (English)In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 74, no 6, p. 061606-Article in journal (Refereed) Published
Abstract [en]

This paper reports a theoretical study of the electrostatic potential within a so-called pen-heterojunction made up of two semi-infinite, doped semiconductor media separated by an electrolyte region. An external potential is then applied across the entire system. Both the electrostatic potentials and double layer surface forces are studied as functions of the usual double layer system properties, semiconductor properties such as doping concentrations of acceptor and donator atoms, as well as applied potential. We find that both attractive and repulsive forces are possible depending on the surface charges on the electrolyte-semiconductor interfaces, and that these forces can be significantly modified by the applied potential and by the doping levels in the semiconductors.

Keywords
electrolytes; semiconductor heterojunctions; semiconductor doping; doping profiles; interface phenomena
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-15727 (URN)10.1103/PhysRevE.74.061606 (DOI)
Available from: 2008-12-04 Created: 2008-12-01 Last updated: 2017-12-14Bibliographically approved
Said, E., Crispin, X., Herlogsson, L., Elhag, S., Robinson, N. D. & Berggren, M. (2006). Polymer field-effect transistor gated via a poly(styrenesulfonic acid) thin film. Applied Physics Letters, 89(14), 143507-
Open this publication in new window or tab >>Polymer field-effect transistor gated via a poly(styrenesulfonic acid) thin film
Show others...
2006 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 89, no 14, p. 143507-Article in journal (Refereed) Published
Abstract [en]

A polyanionic proton conductor, named poly(styrenesulfonic acid) (PSSH), is used to gate an organic field-effect transistor (OFET) based on poly(3-hexylthiophene) (P3HT). Upon applying a gate bias, large electric double layer capacitors (EDLCs) are formed quickly at the gate-PSSH and P3HT-PSSH interfaces due to proton migration in the polyelectrolyte. This type of robust transistor, called an EDLC-OFET, displays fast response (<1  ms) and operates at low voltages (<1  V). The results presented are relevant for low-cost printed polymer electronics.

Place, publisher, year, edition, pages
American Institute of Physics, 2006
Keywords
field effect transistors, organic semiconductors, semiconductor thin films, capacitors, ionic conductivity, polymer electrolytes
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-14682 (URN)10.1063/1.2358315 (DOI)
Available from: 2008-12-04 Created: 2008-11-12 Last updated: 2017-12-13Bibliographically approved
Said, E., Robinson, N. D., Nilsson, D., Svensson, P.-O. & Berggren, M. (2005). Visualizing the Electric Field in Electrolytes Using Electrochromism from a Conjugated Polymer. Electrochemical and solid-state letters, 8(2), H12-H16
Open this publication in new window or tab >>Visualizing the Electric Field in Electrolytes Using Electrochromism from a Conjugated Polymer
Show others...
2005 (English)In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 8, no 2, p. H12-H16Article in journal (Refereed) Published
Abstract [en]

Electrochromic polymer films, employed as display elements, smart windows, and the base material for electrochemical electronic devices, can be addressed solely through ionic transport via an electrolyte, without direct electronic connection as typically employed in the above examples. We present a demonstration of induced electrochromism to quantify the direction and magnitude of the electric field in an electrolyte using poly(3,4-ethylenedioxythiophene) doped with polystyrene-sulfonate. After further development, this simple yet effective technique will be potentially applicable for optimizing batteries and fuel cells, as the active detection element in electrochemical sensors and as a detector in ionic separation in electrolytes (electrophoresis).

Place, publisher, year, edition, pages
The Electrochemical Society, 2005
Keywords
conducting polymers, electrolytes, electric fields, electrochromism, polymer films
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-14681 (URN)10.1149/1.1843751 (DOI)
Available from: 2008-12-04 Created: 2008-11-12 Last updated: 2017-12-13Bibliographically approved
Said, E., Larsson, O., Berggren, M. & Crispin, X.Role of the ionic currents in electrolyte-gated organic field effect transistors.
Open this publication in new window or tab >>Role of the ionic currents in electrolyte-gated organic field effect transistors
(English)Manuscript (Other (popular science, discussion, etc.))
Identifiers
urn:nbn:se:liu:diva-14683 (URN)
Available from: 2008-11-12 Created: 2008-11-12 Last updated: 2018-10-08
Organisations

Search in DiVA

Show all publications