OLED-Integrated Organic Photodiode Layer Tuning for Higher EQE

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Solution Overview

Problem

Existing organic photodiodes (OPDs) face limitations in external quantum efficiency (EQE) and integration with organic light-emitting devices (OLEDs) for applications like fingerprint recognition, despite their advantages in processing, cost, and flexibility.

Innovation Solution

The integration of an organic photodiode with specific layer structures and materials, including a photoactive layer of 200-300 Å thickness and p-type/n-type semiconductors, along with auxiliary layers tailored for wavelength-specific light absorption and resonance, enhances EQE and facilitates integration with OLEDs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the photoactive layer thickness is increased to improve light absorption, then light absorption efficiency is improved, but device complexity and manufacturing precision requirements increase

Engineering Contradiction:
Improvelight absorption efficiencyVSAvoidfilm thickness control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent optimizes the photoactive layer thickness to a specific range (200-300 Å) to achieve optimal light absorption efficiency. This parameter optimization balances the trade-off between absorption efficiency and manufacturing precision, as the specified range provides sufficient absorption while remaining achievable with standard fabrication tolerances.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces auxiliary layers with specific thicknesses (50-150 Å) that differ from the photoactive layer thickness. These auxiliary layers are strategically positioned to compensate for optical resonance effects at specific wavelengths, providing localized optimization without requiring the entire device structure to be redesigned.

Inventive Principle:
Principle #3Local quality

2Reliability

If auxiliary layers are added to compensate for optical resonance distance, then light detection efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvelight detection efficiencyVSAvoidlayer structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The auxiliary layers serve multiple functions: they compensate for optical resonance distance, facilitate hole transport, and maintain structural integrity. By designing layers that perform multiple functions simultaneously, the patent reduces the need for additional specialized components, thereby limiting the increase in device complexity while still improving detection efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the resonance compensation function and hole transport function into the same auxiliary layer structure. Rather than adding separate layers for each function, the auxiliary layers are designed to achieve both objectives simultaneously, reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If the photoactive layer thickness is optimized for resonance matching, then external quantum efficiency is improved, but the range of detectable wavelengths may be limited

Engineering Contradiction:
Improveexternal quantum efficiencyVSAvoidwavelength detection range
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent uses auxiliary layers with different thicknesses (50-150 Å) positioned at different locations to address resonance issues at different wavelengths. This localized approach allows the device to maintain high efficiency at specific wavelengths while preserving broader spectral coverage, as each auxiliary layer targets specific resonance conditions without affecting other wavelength ranges.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs a multi-layer structure where the auxiliary layers can be adjusted or optimized for different wavelength ranges. This dynamic design allows the device to adapt to different detection requirements by modifying the auxiliary layer configuration, thereby maintaining high external quantum efficiency across a broader spectrum.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The proposed structure improves external quantum efficiency and enables efficient light detection, particularly for wavelength-specific applications, while allowing integration with OLEDs for advanced functionalities like fingerprint recognition.

Implementation Method 1

Organic photodiodes (OPDs) use an organic semiconductor to absorb incident light, and convert it into a current

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

organic light-emitting devices (OLEDs)

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP4358675B1Electronic apparatus including organic photodiode and organic light-emitting device
Publication Date: 2026.04.29 SAMSUNG DISPLAY CO LTD
  • EP4358675B1 patent drawingFigure 1
  • EP4358675B1 patent drawingFigure 2
  • EP4358675B1 patent drawingFigure 3

AI summary

Provided is an electronic apparatus including a substrate, a plurality of organic light-emitting devices and an organic photodiode. The organic photodiode includes a first auxiliary layer and a photoactive layer. The plurality of the organic light-emitting include first, second, and third light-emitting devices. The first light-emitting device includes a second auxiliary layer and a first emission layer. The second light-emitting device includes a third auxiliary layer and a second emission layer. The third light-emitting device includes a fourth auxiliary layer and a third emission layer. The photoactive layer may have a thickness in a range of about 200 Å to about 300 Å. The second to the fourth auxiliary layers have different thicknesses from each other. The first auxiliary layer has an identical thickness to a thickness of one selected from the second to the fourth auxiliary layer.