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Tehrani, Payman
Publications (10 of 12) Show all publications
Berggren, M., Nilsson, D., Andersson Ersman, P., Tehrani, P. & Hennerdal, L.-O. (2010). Electrochromic Displays. In: Janelle Leger, Magnus Berggren, Sue Carter (Ed.), Iontronic: Ionic Carriers in Organic Electronic Materials and Devices (pp. 131-139). Boca Raton: CRC Press; Taylor & Francis Group
Open this publication in new window or tab >>Electrochromic Displays
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2010 (English)In: Iontronic: Ionic Carriers in Organic Electronic Materials and Devices / [ed] Janelle Leger, Magnus Berggren, Sue Carter, Boca Raton: CRC Press; Taylor & Francis Group , 2010, p. 131-139Chapter in book (Other academic)
Abstract [en]

The field of organic electronics promises exciting new technologies based on inexpensive and mechanically flexible electronic devices. It has progressed over the past three decades to the point of commercial viability and is projected to grow to a 30 billion dollar market by the year 2015. Exploring new applications and device architectures, this book sets the tone for that exploration, gathering a community of experts in this area who are focused on the use of ionic functions to define the principle of operation in polymer devices. The contributors detail relevant technologies based on organic electronics, including polymer electrochromic devices and light-emitting electrochemical cells.

Place, publisher, year, edition, pages
Boca Raton: CRC Press; Taylor & Francis Group, 2010
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-62541 (URN)978-1-4398-0688-3 (ISBN)978-1-4398-0689-0 (ISBN)
Available from: 2010-11-30 Created: 2010-11-30 Last updated: 2017-02-03Bibliographically approved
Tehrani, P., Engquist, I., Robinson, N. D., Nilsson, D., Robertsson, M. & Berggren, M. (2010). Printable organic electrochemical circuit to record time-temperature history. ELECTROCHIMICA ACTA, 55(23), 7061-7066
Open this publication in new window or tab >>Printable organic electrochemical circuit to record time-temperature history
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2010 (English)In: ELECTROCHIMICA ACTA, ISSN 0013-4686, Vol. 55, no 23, p. 7061-7066Article in journal (Refereed) Published
Abstract [en]

An electrochemical circuit to record time-temperature history has been realized by using the propagation of over-oxidation fronts in stripes of poly(3,4-ethylenedioxythiopehene) blended with poly(styrenesulfonate) (PEDOT:PSS). The over-oxidation front propagation has been characterized and related to the phase change of polyethylene glycol (PEG) electrolytes. The electrolytes were chosen to have a phase transition in the temperature interval to be monitored, resulting in large conductivity variations and thereby an easily interpreted output. A demonstrator has been fabricated and shown to detect a temperature increase and a following temperature decrease. This very simple device is cheap to produce and could be used to monitor the temperature of packages.

Place, publisher, year, edition, pages
Elsevier Science B.V., Amsterdam., 2010
Keywords
Over-oxidation, PEDOT:PSS, Temperature, Timer, Polyethylene glycol
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-60252 (URN)10.1016/j.electacta.2010.06.073 (DOI)000281994700020 ()
Available from: 2010-10-08 Created: 2010-10-08 Last updated: 2017-02-03
Tehrani, P., Hennerdal, L.-O., Dyer, A. L., Reynolds, J. R. & Berggren , M. (2009). Improving the contrast of all-printed electrochromic polymer on paper displays. JOURNAL OF MATERIALS CHEMISTRY, 19(13), 1799-1802
Open this publication in new window or tab >>Improving the contrast of all-printed electrochromic polymer on paper displays
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2009 (English)In: JOURNAL OF MATERIALS CHEMISTRY, ISSN 0959-9428 , Vol. 19, no 13, p. 1799-1802Article in journal (Refereed) Published
Abstract [en]

PEDOT:PSS-based electrochromic displays have been explored for manufacture on flexible paper substrates in roll-to-roll printing presses at high volumes and low costs. Here, we report the improvement of the optical contrast of such devices by adding an extra layer of a dihexyl-substituted poly(3,4-propylenedioxythiophene) (PProDOT-Hx2) to complement the optical absorption spectrum of PEDOT: PSS. The oxidized state of PProDOT-Hx2 is highly transparent and is an intense magenta color while in the reduced state. By adding a layer of PProDOT-Hx2 directly on top of PEDOT: PSS, we were able to improve the optical contrast by nearly a factor of two. In this report, we present optical and electrochemical data of PProDOT-Hx2/PEDOT: PSS-based electrochromic paper displays and compare their performance with PEDOT: PSS-only equivalents.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-17504 (URN)10.1039/b820677e (DOI)
Available from: 2009-03-27 Created: 2009-03-27 Last updated: 2017-02-03
Tehrani, P. (2008). Electrochemical Switching in Conducting Polymers – Printing Paper Electronics. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Electrochemical Switching in Conducting Polymers – Printing Paper Electronics
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

During the last 30 years a new research and technology field of organic electronic materials has grown thanks to a groundbreaking discovery made during the late 70’s. This new field is today a worldwide research effort focusing on exploring a new class of materials that also enable many new areas of electronics applications. The reason behind the success of organic electronics is the flexibility to develop materials with new functionalities via clever chemical design and the possibility to use low‐cost production techniques to manufacture devices.

This thesis reports different aspects of electrochemical applications of organic electronics. We have shown that the color contrast in reflective and transmissive electrochromic displays can be almost doubled by adding an extra electrochromic polymer. The choice of electrochromic material was found to be limited by its electrochemical over‐oxidation (ECO) properties, which is one of the main degradation mechanisms found in displays. The irreversible and non‐conducting nature of over‐oxidized films encouraged us to use it in a novel patterning process in which polythiophene films can be patterned through local and controlled deactivation of the conductivity. ECO can be combined with various patterning tools such as screen printing for low‐cost roll‐to‐roll manufacturing or photolithography, which enables patterning of small features. Studies have shown that electronic conductivity contrasts beyond 107 can be achieved, which is enough for various simple electronic systems. To generate better understanding of the ECO phenomenon, the effect of pH on the over‐oxidation characteristics was studied. The results suggest that a part of the mechanism for over‐oxidation depends on the OH– concentration of the electrolyte used. Over‐oxidation has also been used in electrochemical loggers, where the temperature and time dependence of the propagation of an over‐oxidation front is used to monitor and record the temperature of a package.

Abstract [sv]

Dagligen kommer vi i kontakt med olika plastmaterial. Dessa har vanligtvis mycket dålig elektrisk ledningsförmåga och används oftast som isolerande material. Det finns dock en klass av plaster som är halvledande eller ledande. Sedan upptäckten av dessa material för mer än 30 år sedan har nya material och användningsområden utvecklats och nu börjar de första produkterna baserad på organisk elektronik komma ut på marknaden. En stor fördel med de ledande plasterna är att egenskaperna kan anpassas genom att ändra den kemiska strukturen. Man kan dessutom lösa upp dem och skapa ledande bläck, som sedan kan användas i vanliga tryckmaskiner. Detta gör det möjligt att på ett enkelt och billigt sätt tillverka elektronik på liknande sätt som till exempel tidningar trycks idag.

Den här avhandlingen behandlar en del av det nya området som berör elektrokemiska komponenter och några av dess tillämpningar. Fokus ligger främst på billig, tryckt elektronik. Bland annat presenteras ett sätt att fördubbla kontrasten för tryckta pappersdisplayer, ett nytt sätt att mönstra ledande plaster och elektrokemisk temperaturloggningsetikett som kan övervaka temperaturen för förpackningar under transport. Den mekanism som förstör ledningsförmågan vid höga spänningar har varit ett återkommande inslag i de studier som har genomförts här. Denna mekanism förstör komponenterna under drift men kan också användas för att ta bort ledningsförmågan som mönstringsmetod eller för att lagra information, permanent, i temperaturloggningsetiketten.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2008. p. 37
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1212
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-15132 (URN)9789173938013 (ISBN)
Public defence
2008-10-10, K3, Kåkenhus, Campus Norrköping, Linköpings universitet, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2008-10-17 Created: 2008-10-17 Last updated: 2017-12-14Bibliographically approved
Andersson, P., Forchheimer, R., Tehrani, P. & Berggren, M. (2007). Printable All-Organic Electrochromic Active-Matrix Displays. Advanced Functional Materials, 17(16), 3074-3082
Open this publication in new window or tab >>Printable All-Organic Electrochromic Active-Matrix Displays
2007 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 17, no 16, p. 3074-3082Article in journal (Refereed) Published
Abstract [en]

All-organic active matrix addressed displays based on electrochemical smart pixels made on flexible substrates are reported. Each individual smart pixel device combines an electrochemical transistor with an electrochromic display cell, thus resulting in a low-voltage operating and robust display technology. Poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS) served as the active material in the electrochemical smart pixels, as well as the conducting lines, of the monolithically integrated active-matrix display. Different active-matrix display addressing schemes have been investigated and a matrix display fill factor of 65 % was reached. This is achieved by combining a three-terminal electrochemical transistor with an electrochromic display cell architecture, in which an additional layer of PEDOT:PSS was placed on top of the display cell counter electrode. In addition, we have evaluated different kinds of electrochromic polymer materials aiming at reaching a high color switch contrast. This work has been carried out in the light of achieving a robust display technology that is easily manufactured using a standard label printing press, which forced us to use the fewest different materials as well as avoiding exotic and complex device architectures. Together, this yields a manufacturing process of only five discrete patterning steps, which in turn promise for that the active matrix addressed displays can be manufactured on paper or plastic substrates in a roll-to-roll production procedure.

Keywords
Displays, Electrochromic materials, Electronic paper
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-12766 (URN)10.1002/adfm.200601241 (DOI)
Available from: 2008-11-12 Created: 2008-11-12 Last updated: 2017-12-14
Tehrani, P., Kanciurzewska, A., Crispin, X., Robinson, N. D., Fahlman, M. & Berggren, M. (2007). The effect of pH on the elechtrochemical over-oxidation of PEDOT:PSS films. Solid State Ionics, 177(39-40), 3521-3527
Open this publication in new window or tab >>The effect of pH on the elechtrochemical over-oxidation of PEDOT:PSS films
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2007 (English)In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 177, no 39-40, p. 3521-3527Article in journal (Refereed) Published
Abstract [en]

Chemical degradation of conjugated polymers is one cause of material failures in polymer-based (opto)electronic devices, but can also be used as a technique for subtractive patterning of polymer films. When a large anodic potential is applied to the conducting polymer blend poly(3,4-ethylenedioxythiophene)-poly(4styrenesulfonate), PEDOT:PSS, an over-oxidation reaction occurs, altering its electrical conductivity. Here, we have studied the effect of pH on the electrochemical over-oxidation process of PEDOT in PEDOT:PSS. High pH is associated with a decrease of over-oxidation potential and an increase of resistivity in the resulting film. Vibrational spectroscopy and photoelectron spectroscopy measurements on over-oxidized PEDOT:PSS films indicate that the decrease in conductivity results from cleavage of the conjugation pathway accompanied by the formation of sulfone, carbonyl and carboxylic groups in the polymer chain.

Place, publisher, year, edition, pages
ScienceDirect, 2007
Keywords
Poly(3, 4-ethylenedioxythiophene), Degradation, Over-oxidation, XPS, FTIR, Conjugated polymer, Polythiophenes
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-14026 (URN)10.1016/j.ssi.2006.10.008 (DOI)
Available from: 2008-11-12 Created: 2008-10-17 Last updated: 2017-12-13Bibliographically approved
Tehrani, P. (2006). Electrochromism and over-oxidation in conjugated polymers: Improved color switching and a novel patterning approach. (Licentiate dissertation). Institutionen för teknik och naturvetenskap
Open this publication in new window or tab >>Electrochromism and over-oxidation in conjugated polymers: Improved color switching and a novel patterning approach
2006 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

During the last 30 years a new research and technology field of organic electronic materials has grown thanks to a groundbreaking discovery made during the late 70’s. This new field is today a worldwide research effort focusing on exploring this new class of materials that also enable many new areas of electronics applications. In the organic electronics research field conducting organic molecules and polymers are synthesized and used in devices. The reason behind the success of conducting polymers is the flexibility to develop materials with new functionalities via clever chemical design and the possibility to use low-cost production techniques to manufacture devices.

This thesis reviews and describes different aspects of the organic electronics, here focusing on electrochromic displays; device improvements, the study of degradation and also patterning technology for rational manufacturing processing. The color contrast in electrochromic displays based on conjugated polymers was increased with approximately a factor of two by adding an extra electrochromic polymer. It was found that electrochemical over-oxidation (ECO) limits the flexibility in choosing desired electrochromic materials. ECO is one of the main degradation mechanisms in electrochromic displays. ECO is an efficient and fast process to permanently reduce the electronic conductivity in polythiophenes. From this, a novel patterning process was developed, in which the films of polythiophenes can be patterned through local and controlled deactivation of the conductivity. The ECO has been combined with different patterning tools to enable the use of existing printing tools for manufacturing. In combination with screen-printing, low-cost and high volume roll-to-roll patterning was demonstrated, while together with photolithography, patterning down to 2 µm can be achieved. Systematic studies have shown that conductivity contrasts beyond 107 can be achieved, which is enough for various simple electronic systems. To generate better understanding of the ECO phenomena the effect of pH on the over-oxidation characteristics was studied. The results suggest that a part of the mechanism for over-oxidation depends on the OH– concentration of the electrolyte used.

Place, publisher, year, edition, pages
Institutionen för teknik och naturvetenskap, 2006. p. 31
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1237
Keywords
Conjugated polymers, Over-oxidation, Patterning, Electrochromism, PEDOT:PSS
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:liu:diva-7478 (URN)LiU-TEK-LIC- 2006:17 (Local ID)91-85497-34-7 (ISBN)LiU-TEK-LIC- 2006:17 (Archive number)LiU-TEK-LIC- 2006:17 (OAI)
Presentation
2006-03-02, TP2, Täppan, LiU Norrköping, Norrköping, 14:15 (English)
Opponent
Supervisors
Available from: 2006-10-04 Created: 2006-10-04 Last updated: 2017-02-03
Tehrani, P., Isaksson, J., Mammo, W., Andersson, M., Robinson, N. D. & Berggren, M. (2006). Evaluation of active materials designed for use in printable electrochromic polymer displays. Thin Solid Films, 515(4), 2485-2492
Open this publication in new window or tab >>Evaluation of active materials designed for use in printable electrochromic polymer displays
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2006 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 4, p. 2485-2492Article in journal (Refereed) Published
Abstract [en]

In a step towards roll-to-roll production of polymer-based electrochromic displays on flexible substrates, nine thiophene-based polymers and copolymers designed to increase the contrast of displays based on poly(3,4-ethylenedioxythiophene)/poly(styrene-sulfonic acid) have been synthesized and evaluated with respect to their absorbance (contrast), switch speed, and ability to switch reversibly in a water-based electrolyte. The results of the evaluation, including cyclic voltammetry and optically visible absorption, provide a basis for understanding what an aqueous electrolyte electrochromic display requires in terms of oxidation potential and material stability, and the effect of chemical structure on the reversibility and speed of switching. © 2006 Elsevier B.V. All rights reserved.

Keywords
Electrochromic display; Conjugated polymers; Poly(3, 4-ethylenedioxythiophene)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-37443 (URN)10.1016/j.tsf.2006.07.149 (DOI)35830 (Local ID)35830 (Archive number)35830 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
Andersson, P., Tehrani, P., Forchheimer, R., Nilsson, D., Robinson, N. D. & Berggren, M. (2005). All-Organic Active Matrix Addressed Displays Based on Electrochromic Polymers and Flexible Substrate. In: MRS Fall Meeting,2005.
Open this publication in new window or tab >>All-Organic Active Matrix Addressed Displays Based on Electrochromic Polymers and Flexible Substrate
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2005 (English)In: MRS Fall Meeting,2005, 2005Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-32391 (URN)18291 (Local ID)18291 (Archive number)18291 (OAI)
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-02-03
Tehrani, P., Robinson, N. D., Kugler, T., Remonen, T., Hennerdal, L.-O., Häll, J., . . . Berggren, M. (2005). Patterning polythiophene films using electrochemical over-oxidation. Smart materials and structures (Print), 14, N21-N25
Open this publication in new window or tab >>Patterning polythiophene films using electrochemical over-oxidation
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2005 (English)In: Smart materials and structures (Print), ISSN 0964-1726, E-ISSN 1361-665X, Vol. 14, p. N21-N25Article in journal (Refereed) Published
Abstract [en]

Over-oxidative degradation of polythiophenes, which breaks the conjugation and destroys the electronic conductivity of the polymer, is well documented as a liability in these materials. We use this 'weakness', via controlled electrochemical over-oxidation, in a novel subtractive patterning technique compatible with high-speed reel-to-reel printing technology. We demonstrate the use of electrochemical over-oxidation to pattern PEDOT:PSS films via an x–y plotter, silk-screen and high-resolution photolithographic techniques, resulting in patterning down to a resolution of 2 µm and a conduction contrast between unpatterned and patterned areas of up to 108.

Place, publisher, year, edition, pages
IOP Elctronic Journals, 2005
Keywords
Not Available.
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-14024 (URN)10.1088/0964-1726/14/4/N03 (DOI)
Available from: 2008-11-12 Created: 2008-10-17 Last updated: 2017-12-13Bibliographically approved
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