Organic Photodetector Activation Layer Roughness for Sensitivity
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Solution Overview
Problem
Existing photodiodes face challenges in sensitivity and integration as pixel sizes decrease, leading to a need for alternative materials that can replace silicon and improve light detection efficiency.
Innovation Solution
An electronic apparatus incorporating an organic photodetector with a specific structure, including a substrate with photodetection and emission regions, a first pixel electrode, a counter electrode, a hole transport region, an activation layer, and an electron transport region, where the electron transport region and activation layer are in contact and have a mean square roughness of 9 nm or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon is used in photodiodes, then manufacturing maturity is maintained, but sensitivity deteriorates as pixel size decreases
Solution Approach 1:
The patent changes the material parameter from silicon to organic materials, which have different optical properties including larger extinction coefficients. This material substitution allows the photodetector to maintain or improve sensitivity even when the absorption region size is reduced, directly addressing the sensitivity deterioration problem in small pixels
Solution Approach 2:
The patent employs composite organic material structures including multiple layers with different functions (hole transport region, electron transport region, emission layer) to achieve superior optical and electrical properties that overcome the limitations of single-material silicon photodiodes in small pixel configurations
2Reliability
If organic materials are used to replace silicon, then sensitivity and integration are improved, but manufacturing complexity increases
Solution Approach 1:
The organic photodetector structure is designed to perform multiple functions within a unified architecture: light absorption, charge separation, charge transport, and light emission. This multi-functionality reduces the need for separate components and simplifies the overall device structure, counteracting the potential increase in manufacturing complexity
Solution Approach 2:
The patent merges the photodetector and light-emitting device into a single integrated structure where the electron transport region and emission layer are in contact, allowing both functions to coexist in one device and facilitating high integration while managing manufacturing complexity
3Measurement precision
If pixel size is decreased, then resolution is improved, but absorption region decreases leading to sensitivity deterioration
Solution Approach 1:
The patent changes the material composition to organic materials with larger extinction coefficients, which enhance light absorption capability. This parameter change in material properties compensates for the reduced absorption region volume in smaller pixels, allowing sensitivity to be maintained or improved despite pixel size reduction
Solution Approach 2:
The patent optimizes the local properties of the organic material layers, particularly the electron transport region and emission layer, to maximize light absorption and charge generation efficiency within the limited space of small pixels. The specific layer structures and material selections are tailored to enhance local absorption and transport properties
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 solution enhances the efficiency of the organic photodetector by improving light detection sensitivity and integration, facilitating the integration of photodetection and light emission functions in a single device.
Implementation Method 1
Photoelectric devices are devices that convert light to electrical signals and include a photodiode and a phototransistor
Implementation Method 2
As organic materials have a large extinction coefficient and may selectively absorb light in a specific wavelength region according to their molecular structures
Data Source
AI summary
Provided is an electronic apparatus including an organic photodetector and a light-emitting device, wherein a mean square roughness (Rq) value of a surface of an activation layer of the organic photodetector in a direction of contact with an electron transport region is 9 nm or more.