Organic Sensor Protective Layer for Low-Capacitance Pixel Scaling
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Solution Overview
Problem
Organic sensors face performance degradation due to the sensitivity issues caused by smaller pixel sizes and reduced absorption areas, which existing technologies have not adequately addressed.
Innovation Solution
An organic sensor design incorporating a first electrode, an organic active layer, a protective layer, and a second electrode, where the protective layer is thin, non-uniform, and includes organic or carbon-containing materials to prevent damage from plasma during the sputtering process, maintaining low capacitance and ensuring effective light absorption and conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is added to protect the organic active layer during sputtering, then the organic active layer is protected from plasma damage, but the capacitance increases
Solution Approach 1:
The protective layer has non-uniform thickness with different regions serving different functions: thicker regions (1-6 nm) provide plasma protection during sputtering, while thinner regions maintain low capacitance for high-speed operation. This local variation in thickness resolves the contradiction between protection and speed.
Solution Approach 2:
The protective layer uses specific material compositions (organic materials with molecular weights 50-5000 Da, carbon-containing materials) and controlled thickness parameters (1-6 nm) to achieve both protection and low capacitance. By optimizing these parameters, the patent resolves the contradiction between reliability and speed.
2Measurement precision
If the pixel size is reduced to increase sensor resolution, then the sensor resolution is improved, but the sensitivity deteriorates due to reduced absorption area
Solution Approach 1:
The patent uses thin film structures (protective layer 1-6 nm, organic active layer with controlled thickness) to maintain high absorption efficiency in small pixels. The thin protective layer allows sufficient light transmission to the organic active layer, ensuring sensitivity is maintained even as pixel size decreases for higher resolution.
3Reliability
If the protective layer thickness is increased to improve protection, then the plasma protection is enhanced, but the manufacturing precision and performance are degraded
Solution Approach 1:
The protective layer thickness is optimized to provide just sufficient plasma protection (1-6 nm) without excessive thickness that would degrade performance. This partial action approach achieves the minimum necessary protection while maintaining manufacturing precision and sensor performance.
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 solution effectively reduces performance degradation by protecting the organic active layer, maintaining sensitivity, and enhancing the overall efficiency of the organic sensor.
Implementation Method 1
an organic active layer between the first electrode and the second electrode... The organic active layer may be a photoelectric conversion layer that is configured to absorb light in at least a portion of a wavelength region and convert the absorbed light into an electric signal
Implementation Method 2
forming a second electrode on the protective layer by sputtering... to prevent damage from plasma during the sputtering process
Data Source
AI summary
An organic sensor includes a first electrode, a second electrode, an organic active layer between the first electrode and the second electrode, and a protective layer between the organic active layer and the second electrode. Capacitance provided of the first electrode, the protective layer, and the second electrode is less than or equal to about 2×10−10 F.