umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Light-Emitting Paper
Umeå University, Faculty of Science and Technology, Department of Physics. LunaLEC, Umeå, Sweden. (The Organic Photonics & Electronics Group)
Umeå University, Faculty of Science and Technology, Department of Physics.
Show others and affiliations
2015 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 25, no 21, 3238-3245 p.Article in journal (Refereed) Published
Abstract [en]

A solution-based fabrication of flexible and light-weight light-emitting devices on paper substrates is reported. Two different types of paper substrates are coated with a surface-emitting light-emitting electrochemical cell (LEC) device: a multilayer-coated specialty paper with an intermediate surface roughness of 0.4 μm and a low-end and low-cost copy paper with a large surface roughness of 5 μm. The entire device fabrication is executed using a handheld airbrush, and it is notable that all of the constituent layers are deposited from solution under ambient air. The top-emitting paper-LECs are highly flexible, and display a uniform light emission with a luminance of 200 cd m−2 at a current conversion efficacy of 1.4 cd A−1.

Place, publisher, year, edition, pages
2015. Vol. 25, no 21, 3238-3245 p.
Keyword [en]
Ag nanowires, all-ambient fabrication, light-emitting electrochemical cells, paper substrates, spray coating
National Category
Other Physics Topics Nano Technology
Identifiers
URN: urn:nbn:se:umu:diva-101921DOI: 10.1002/adfm.201500528ISI: 000355635300015OAI: oai:DiVA.org:umu-101921DiVA: diva2:805641
Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2017-12-04Bibliographically approved
In thesis
1. Functional and Flexible Light-Emitting Electrochemical Cells
Open this publication in new window or tab >>Functional and Flexible Light-Emitting Electrochemical Cells
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The introduction of artificial illumination has brought extensive benefits to mankind, and during the last years we have seen a tremendous progress in this field with the introduction of the energy-efficient light-emitting diode (LED) and the high-contrast organic LED display. These high-end technologies are, however, produced using costly and complex processes, and it is anticipated that the next big thing in the field will be the advent of a low-cost and “green” illumination technology, which can be fabricated in a cost- and material-efficient manner using non-toxic and abundant raw materials, and which features attractive form factors such as flexibility, robustness and light-weight. The light-emitting electrochemical cell (LEC) is a newly invented illumination technology, and in this thesis we present results that imply that it can turn the above vision into reality.

The thin-film LEC comprises an active material sandwiched between a cathode and an anode as its key constituent parts. With the aid of a handheld air-brush, we show that functional large-area LECs can be fabricated by simply spraying three layers of solution -- forming the anode, active material, and cathode -- on top of a substrate. We also demonstrate that such “spray-sintered” LECs can feature multicolored emission patterns, and be fabricated directly on complex-shaped surfaces, with one notable example being the realization of a light-emission fork!

Almost all LECs up-to-date have been fabricated on glass substrates, but for a flexible and light-weight emissive device, it is obviously relevant to identify more appropriate substrate materials. For this end, we show that it is possible to spray-coat the entire LEC directly on conventional copy paper, and that such paper-LECs feature uniform light-emission even under heavy bending and flexing.

We have further looked into the fundamental aspects of the LEC operation and demonstrated that the in-situ doping formation, which is a characteristic and heralded feature of LECs, can bring problems in the form of doping-induced self-absorption. By quantitatively analyzing this phenomenon, we provided straightforward guidelines on how future efficiency-optimized LEC devices should be designed.

The in-situ doping formation process brings the important advantage that LECs can be fabricated from solely air-stabile materials, but during light emission the device needs to be protected from the ambient air. We have therefore developed a functional glass/epoxy encapsulation procedure for the attainment of LEC devices that feature a record-long ambient-air operational lifetime of 5600 h. For the light-emission device of the future, it is however critical that the encapsulation is flexible, and in our last study, we show that the use of multi-layer barrier can result in high-performance flexible LECs.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2015. 57 p.
Keyword
all-ambient fabrication, ambient-air lifetime, encapsulation, flexible, light-emitting electrochemical cells, light-emitting paper
National Category
Nano Technology Other Physics Topics
Research subject
Physics
Identifiers
urn:nbn:se:umu:diva-102400 (URN)978-91-7601-257-4 (ISBN)
Public defence
2015-05-22, N300, Naturvetarhuset, Umeå University, Umeå, 10:00 (English)
Opponent
Supervisors
Available from: 2015-04-30 Created: 2015-04-23 Last updated: 2015-05-08Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Asadpoordarvish, AmirLarsen, ChristianEdman, Ludvig
By organisation
Department of Physics
In the same journal
Advanced Functional Materials
Other Physics TopicsNano Technology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 1268 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf