Workshop on Fundamental Research Needs in Organic Electronic Materials (May 23-25, 2003) Page: 4 of 6
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
Other research areas in need of attention include: (i) Carrier injection, related with ohmic
and non-ohmic contacts. (ii) Spin effects, such as singlets versus triplets, and their
relative formation cross-sections. (iii) Interfaces, such as organic/metal, organic/dielectric
and organic/organic. (iv) Quenching of electroluminescence processes have been
identified, such as quenching by metallic electrodes, by injected polarons and triplets, and
quenching by electric field. (v) Theory and modeling. (vi) Morphology can drastically
affect the OLED performance; a systematic study of morphology effects on OLED's
performance is in order. (vii) Light extraction is an acute problem in OLED's. Various
methods have been devised to extract more light, and their systematic study is needed.
(viii) Material purity and new organic semiconductors; the exact relation between
material purity and OLED performance is lacking. Also the question whether the field
needs new organic active layers was discussed. (ix) Various ways of achieving white
light were mentioned during the meeting and thoroughly discussed.
(c) Organic transistors; Organic field effect transistors, OFET's now routinely have
mobilities > 0.1 cm2/volt-sec, which is sufficient for many applications. This has been
achieved for both p-channel and n-channel devices. The improved OFET devices have
led to prototypes of electronic ID tags, electronic paper, and active matrix liquid crystal
displays. There is also increasing interest in OFET-driven active matrix driven
OLED/PLED displays. In universities and industrial laboratories in the U.S, Europe and
Asia there has been remarkable progress in the application of soft-lithography, novel
forms of patterning, and printing techniques to the fabrication of transistor based devices
and circuits. Development of new materials and material families for both the
semiconductor and insulator regions of the field effect devices are expected, needed and
represent an important opportunity.
There are several issues in this area, which warrant detailed studies. These include the
following: Grain boundary effects, injection into the FET device, the role of defects, and
local crystallinity, reversed sweeping and cycling stress-effects, and long time-scale
relaxation effects. Understanding the maximum room-temperature mobility remains an
active issue: Is there a theoretical limit? More generally, detailed device modeling is
needed with associated experimental work; it was stressed that details of the device
operation are not the same as in the inorganic counterparts. Continued research on new
materials, particularly n-channel FET materials and materials exhibiting ambipolar
transport for logic and light-emission, will be needed.
(d) Photovoltaic (PV) and solar cells; This is an important focus area where a sizable
amount of research is expected to be directed over the coming years. The most important
potential advantage of organic PV is cost. The cost barrier to wider use of solar cells has
been keenly felt by existing technologies (such as crystalline silicon and hydrogenated
amorphous silicon) that have matured over the last two decades. Organic semiconductors,
if they can achieve the reliability needed, may be able to provide a cost-effective
alternative. At present, however power conversion efficiencies are in the neighborhood of
7% in the best organic solar cells. This will need to improve by at least a factor of two to
~14% as a distant goal of the field. One of the biggest challenges is the carrier mobility
that currently limits the charge collection efficiency. Improved mobilities will increase4
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Vardeny, Prof. Zeev Valentine. Workshop on Fundamental Research Needs in Organic Electronic Materials (May 23-25, 2003), report, May 26, 2007; United States. (https://digital.library.unt.edu/ark:/67531/metadc878843/m1/4/: accessed April 24, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.