Quasi-Surface Emission Vertical Organic Light-Emitting Transistors

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Solution Overview

Problem

Existing organic light-emitting transistors have limited light emission area and efficiency due to line-type emission characteristics and poor connectivity from random carbon nano-tube distribution, which affects stability and reproducibility.

Innovation Solution

A quasi-surface emission vertical-type organic light-emitting transistor with a mesh-type source electrode having apertures in an array pattern, reducing the need for additional driving elements and enhancing light emission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a mesh-type source electrode with apertures in array pattern is used, then light emission efficiency and aperture ratio are improved, but device complexity increases

Engineering Contradiction:
Improvelight emission efficiencyVSAvoidelectrode structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The source electrode is segmented into a mesh-type structure with multiple apertures arranged in an array pattern, allowing light to emit through multiple discrete regions simultaneously, thereby increasing overall light emission efficiency and aperture ratio

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mesh-type source electrode is integrated within the vertical-type transistor structure, with the electrode pattern nested within the overall device architecture, achieving enhanced light emission without proportionally increasing device footprint

Inventive Principle:
Principle #7Nested doll (Nesting)

2Area of stationary object

If carbon nano-tubes are used as source electrode, then light emission area is increased, but stability and lifetime are reduced due to random distribution and surface roughness

Engineering Contradiction:
Improvelight emission areaVSAvoiddevice stability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The source electrode uses a homogeneous mesh-type pattern with uniformly distributed apertures, eliminating the random distribution and surface roughness problems associated with carbon nano-tube assemblies, thereby improving device stability and reproducibility

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The source electrode structure is changed from random carbon nano-tube distribution to a controlled mesh pattern with specific aperture dimensions (200 μm or below) and spacing, transforming the physical parameters to achieve both large emission area and high stability

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If source and drain electrodes are laterally located on the same plane, then device structure is simplified, but light emission area is limited to small region

Engineering Contradiction:
Improveelectrode arrangementVSAvoidlight emission area
Core Design Contradiction:
Device complexityVSArea of stationary object

Solution Approach 1:

The device transitions from a planar lateral electrode arrangement to a vertical-type structure where the mesh source electrode is positioned above the semiconductor layer, enabling light emission from the top surface and dramatically increasing the effective light emission area

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2760060B1Quasi-surface emission vertical-type organic light-emitting transistors and method of manufacturing the same
Publication Date: 2021.04.21 SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION
  • EP2760060B1 patent drawingFigure 1a~1b
  • EP2760060B1 patent drawingFigure 2a~2b
  • EP2760060B1 patent drawingFigure 3a~3d

AI summary

An organic light-emitting transistor may include a mesh-type source electrode (40) having a plurality of apertures (400) in an array pattern. The mesh-type source electrode (40) may be located between the gate electrode (20) and the drain electrode (80). The organic light-emitting transistor adopting a mesh-type source electrode (40) may show quasi-surface emission characteristics similar to that of the organic light-emitting diode. Moreover, an aperture ratio, brightness, and light emission efficiency of the organic light-emitting transistor may be superior to those of an organic light-emitting diode. Another advantage is that the production cost may be reduced since an additional driving element such as a thin-film-transistor is not needed.