Photoelectric Device Nanostructure Wavelength Selectivity
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Solution Overview
Problem
Silicon photodiodes have limited sensitivity due to small absorption areas, leading to lower photoelectronic conversion efficiency, and organic materials, while offering higher extinction coefficients, exhibit recombination behavior that further reduces efficiency.
Innovation Solution
A photoelectric device with a photoelectric conversion layer comprising a p-type and n-type semiconductor forming a pn junction, where the p-type semiconductor selectively absorbs visible light, and nanostructures between the electrodes reflect specific wavelengths, increasing light absorption and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If silicon photodiode is used to achieve high resolution, then pixel size can be reduced, but absorption area decreases and sensitivity deteriorates
Solution Approach 1:
The patent introduces a vertical dimension by stacking multiple photoelectric conversion layers with different light-absorbing characteristics. This allows the device to maintain small pixel size for high resolution while increasing the total light absorption area through vertical stacking, thereby improving sensitivity without sacrificing resolution.
Solution Approach 2:
The patent uses composite photoelectric conversion layers combining organic and inorganic materials with complementary light-absorbing properties. The organic layer absorbs specific wavelength ranges while the inorganic layer absorbs other ranges, creating a composite structure that enhances overall light absorption efficiency and sensitivity within the constrained pixel area.
2Reliability
If organic material is used to replace silicon, then extinction coefficient increases and sensitivity improves, but recombination behavior increases and photoelectronic conversion efficiency decreases
Solution Approach 1:
The patent creates a composite photoelectric conversion layer combining organic materials (with high extinction coefficient and wavelength selectivity) and inorganic materials (with better charge transport and lower recombination). The organic component absorbs light efficiently and selectively, while the inorganic component facilitates efficient charge separation and transport, compensating for the recombination issues in pure organic materials.
Solution Approach 2:
The patent assigns different functional qualities to different regions of the photoelectric conversion layer. The organic material provides localized light absorption and wavelength selectivity, while the inorganic material provides localized charge transport and recombination suppression. This spatial division of functional qualities allows the device to benefit from both material types without suffering from their individual weaknesses.
3Reliability
If multiple photoelectric conversion layers are stacked, then light absorption characteristics improve, but device complexity increases
Solution Approach 1:
The patent resolves the complexity issue by stacking photoelectric conversion layers vertically rather than expanding horizontally. This vertical stacking approach improves light absorption characteristics by providing multiple absorption opportunities for different wavelengths, while maintaining a compact footprint that doesn't significantly increase overall device complexity.
Solution Approach 2:
The patent designs the stacked photoelectric conversion layers to serve multiple functions simultaneously: each layer provides wavelength-selective absorption, the stack collectively broadens the spectral response, and the alternating organic-inorganic structure provides both absorption and charge transport functions. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
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
Enhances light absorption characteristics and wavelength selectivity, improving photoelectronic conversion efficiency by selectively reflecting and re-absorbing light, thereby increasing the external quantum efficiency.
Implementation Method 1
A photoelectric device may convert light into an electrical signal using photoelectric effects
Implementation Method 2
a plurality of nanostructures between the first electrode and the photoelectric conversion layer and configured to selectively reflect the first visible light
Implementation Method 3
The photoelectric conversion layer may include a p-type semiconductor and an n-type semiconductor to form a pn junction
Data Source
AI summary
A photoelectric device includes a first electrode and a second electrode facing each other, a photoelectric conversion layer between the first electrode and the second electrode and including a light absorbing material configured to selectively absorb first visible light including one of visible light in a blue wavelength region of greater than or equal to about 380 nm and less than about 500 nm, visible light in a green wavelength region of about 500 nm to about 600 nm, and visible light in a red wavelength region of greater than about 600 nm and less than or equal to about 700 nm, and a plurality of nanostructures between the first electrode and the photoelectric conversion layer and configured to selectively reflect the first visible light.