Organic Photoelectronic Device with Dual-Layer Composition Ratios
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Solution Overview
Problem
Silicon photodiodes used in image sensors have limited sensitivity and absorption area due to small pixels, and organic materials, while offering higher sensitivity and wavelength selectivity, suffer from low efficiency and heat resistance compared to silicon-based devices.
Innovation Solution
An organic photoelectronic device with a layered structure comprising a p-type and n-type semiconductor in specific composition ratios, where the first layer has a higher p-type to n-type ratio and the second layer has a lower ratio, enhancing wavelength selectivity and heat resistance, is developed. This device includes a p-type semiconductor with a core structure and an n-type semiconductor like fullerene, selectively absorbing light in specific wavelength regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If organic material is used to replace silicon photodiode, then wavelength selectivity and sensitivity are improved, but efficiency and heat resistance deteriorate
Solution Approach 1:
The patent uses a composite structure consisting of two different organic photoelectronic conversion layers with distinct p-type to n-type semiconductor ratios. The first layer has a higher ratio (p1/n1 > 1.5) optimized for wavelength selectivity, while the second layer has a lower ratio (p2/n2 < 1.5) optimized for efficiency and heat resistance. This composite approach allows the device to simultaneously achieve both wavelength selectivity and improved reliability.
Solution Approach 2:
Different regions of the photoelectronic conversion element have different compositions tailored to specific functions. The first photoelectronic conversion layer is designed with specific material composition for wavelength selectivity, while the second layer has different composition for efficiency and thermal stability. This local differentiation of material properties resolves the contradiction between wavelength selectivity and heat resistance.
2Measurement precision
If pixel size is reduced for high resolution, then image sensor resolution is improved, but absorption area and sensitivity deteriorate
Solution Approach 1:
The composite structure of two photoelectronic conversion layers with different semiconductor ratios enables the device to maintain high sensitivity equivalent to larger pixels while being implemented in smaller pixel dimensions for high resolution. The synergistic effect of the two layers compensates for the reduced absorption area.
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 organic photoelectronic device demonstrates improved wavelength selectivity and heat resistance, increasing external quantum efficiency and maintaining performance after heat treatment, thus addressing the limitations of silicon photodiodes and organic materials.
Implementation Method 1
an organic photoelectronic device converts light into an electrical signal using photoelectronic effects
Implementation Method 2
The organic material has a relatively high extinction coefficient and selectively absorbs light in a particular wavelength region depending on a molecular structure
Data Source
AI summary
An organic photoelectronic device includes a first electrode and a second electrode facing each other, and first and second photoelectronic conversion layers between the first electrode and the second electrode. The first and second photoelectronic conversion layers include a p-type semiconductor and an n-type semiconductor. The first photoelectronic conversion layer has a first composition ratio (p1/n1) of the p-type semiconductor relative to the n-type semiconductor, the second photoelectronic conversion layer has a second composition ratio (p2/n2) of the p-type semiconductor relative to the n-type semiconductor, and the first composition ratio (p1/n1) is greater than the second composition ratio (p2/n2).