New strategy for efficient OLED active matrix displays

Date:
March 2, 2021
Source:
Technische Universita"t Dresden
Summary:
Researchers introduce a novel device concept towards high-efficient
and low-voltage vertical organic lighting-emitting transistors. With
the new device architecture and fabrication technology, the team
paves the way for a broad application of efficient OLED active
matrix displays.



FULL STORY ==========================================================================
In the group of Prof. Karl Leo, physicists, material scientists and
engineers are working jointly on the development of novel organic
materials and devices for high performance, flexible and possibly even biocompatible electronics and optoelectronics of the future. Increasing
the performance of organic devices is one of the key challenges in their research. It was only last year, when the team headed by Dr. Hans Kleemann announced an important breakthrough with the development of efficient, printable vertical organic transistors.


==========================================================================
Now Dr. Zhongbin Wu, Dr. Yuan Liu, and PhD student Erjuan Guo present
the first electronic device that combines a vertical organic permeable
base transistor (OPBT) and an OLED. With this novel device concept
of an organic permeable base light-emitting transistor (OPB-LET), the researchers succeeded in combining the function of a highly efficient
switching transistor and an organic light- emitting diode as commonly
employed in active matrix displays. Active matrix liquid crystal
displays (AMLCD) usually contain a matrix of thin-film transistors
to drive LCD pixels. Each individual pixel has a circuit with active
components (mostly transistors). In this context, organic light-emitting transistors, three-terminal devices combining a thin-film transistor with
a light-emitting diode, have generated increasing interest. However,
increasing their efficiency while keeping the operating voltage low
remains a key challenge.

"The key to construct the high performance OPB-LETs is the permeable base electrode located at the center of the device, forming a distinctive
optical microcavity and regulating charge carrier injection and
transport. The thus designed three-terminal vertical optoelectronic
devices can simultaneously high efficiencies (up to 24.6%), high
luminance (up to 12,513 cd m-2), and low driving voltages (<5.0 V),"
explains Erjuan Guo.

The performance of OPB-LETs demonstrated in this work is
comparable to state- of-the-art OLEDs and cutting-edge,
low-voltage organic transistors. Prof. Karl Leo explains: "We
expect that this novel device principle will pave the way for
highly-efficient flexible displays with a rather simple pixel design." ========================================================================== Story Source: Materials provided by Technische_Universita"t_Dresden. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Zhongbin Wu, Yuan Liu, Erjuan Guo, Ghader Darbandy, Shu-Jen Wang,
Rene'
Hu"bner, Alexander Kloes, Hans Kleemann, Karl Leo. Efficient
and low- voltage vertical organic permeable base light-emitting
transistors.

Nature Materials, 2021; DOI: 10.1038/s41563-021-00937-0 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/03/210302104800.htm

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