Near-Infrared Photoelectric Layer Composition for Low Dark Current
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Solution Overview
Problem
Current near-infrared sensors face challenges in improving electrical characteristics, particularly in reducing dark current under reverse bias voltage, which affects their sensitivity and efficiency in low-illumination environments.
Innovation Solution
A near-infrared sensor design incorporating a near-infrared photoelectric conversion layer with a specific composition ratio of first and second materials, forming a pn junction, where the second material has a wider energy bandgap and deeper HOMO energy level, and optionally including charge auxiliary layers to control hole and electron mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional near-infrared photoelectric conversion layer is used, then the sensor can detect near-infrared light, but the dark current is high under reverse bias voltage
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratio of first and second materials in the photoelectric conversion layer, adjusting the energy bandgap and HOMO energy level parameters to optimize both dark current reduction and photoelectric conversion efficiency simultaneously
Solution Approach 2:
The patent uses composite materials by combining first material (with narrower energy bandgap) and second material (with wider energy bandgap) in specific ratios to form a pn junction structure that achieves both low dark current and high photoelectric conversion efficiency
2Productivity
If the composition ratio of first and second materials is optimized, then photoelectric conversion efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating distinct regions with different material compositions and properties within the photoelectric conversion layer, where the first material-rich region and second material-rich region provide different functional characteristics that together enhance overall performance
Solution Approach 2:
The patent uses segmentation by dividing the photoelectric conversion layer into functionally distinct regions based on material composition, with the pn junction formed by the interface between first and second material regions, allowing independent optimization of each region's 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 design effectively reduces dark current and enhances photoelectric conversion efficiency, improving sensitivity and performance in low-illumination conditions.
Implementation Method 1
a near-infrared photoelectric conversion layer between the anode and the cathode. The near-infrared photoelectric conversion layer may be configured to absorb light of at least a portion of a near-infrared wavelength spectrum and convert the absorbed light into an electrical signal
Data Source
AI summary
A sensor includes an anode and a cathode, and a near-infrared photoelectric conversion layer between the anode and the cathode. The near-infrared photoelectric conversion layer is configured to absorb light of at least a portion of a near-infrared wavelength spectrum and convert the absorbed light into an electrical signal. The near-infrared photoelectric conversion layer includes a first material having a maximum absorption wavelength in the near-infrared wavelength spectrum and a second material forming a pn junction with the first material and having a wider energy bandgap than an energy bandgap of the first material. The first material is included in the near-infrared photoelectric conversion layer in a smaller amount than the second material.