Photodetector Organic Layer Segmentation for Leakage Current Suppression
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Solution Overview
Problem
Current photodetectors face challenges in improving detection characteristics, particularly in suppressing leakage current and enhancing time responsiveness, which affects their sensitivity and response efficiency.
Innovation Solution
A photodetector design incorporating a first conductive layer, an organic layer with distinct regions, and a second conductive layer, where the organic layer includes a first compound with a mother skeleton and a third compound differing from the first, with the second region having a lower concentration of a second compound, facilitating reduced leakage current and improved responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional photodetector structure is used, then the device is simple to manufacture, but leakage current is high and detection sensitivity is low
Solution Approach 1:
The organic layer is segmented into three distinct regions (first, second, and third regions) with different compositions. The first region contains the first and second compounds, the second region contains only the first compound, and the third region contains the first and third compounds. This segmentation allows each region to perform specific functions: the first and third regions facilitate charge generation and transport, while the second region acts as a low-leakage current zone, thereby improving detection sensitivity without requiring overly complex manufacturing processes.
Solution Approach 2:
Different regions of the organic layer are assigned different local qualities through varying compound concentrations. The first compound concentration is highest in the second region to minimize leakage current, while the second and third compounds are concentrated in the first and third regions to enhance charge generation and transport. This local quality differentiation optimizes detection sensitivity while maintaining manufacturing feasibility.
2Speed
If the organic layer uses a single uniform composition, then the manufacturing process is simple, but time responsiveness is poor
Solution Approach 1:
The organic layer is divided into three regions with distinct compositions optimized for different functional requirements. The first region with the second compound enables efficient charge generation, the second region with high first compound concentration provides fast charge transport with minimal leakage, and the third region with the third compound facilitates charge collection. This segmentation achieves high-speed response characteristics that cannot be obtained with a uniform composition.
Solution Approach 2:
The composition parameters of the organic layer are changed across different regions to optimize performance. The concentrations of the first, second, and third compounds are varied spatially: the first compound concentration increases from the first to second region, while the second and third compound concentrations decrease toward the third region. These parameter changes enable rapid charge generation and transport, achieving high time responsiveness.
3Reliability
If the second compound concentration is high throughout the organic layer, then charge generation is efficient, but leakage current increases
Solution Approach 1:
The second compound, which generates charges but also contributes to leakage current when present in high concentrations, is extracted from the second region of the organic layer. By removing the second compound from the central region and concentrating it only in the first region, the invention achieves efficient charge generation at the interface while creating a low-leakage current zone in the middle region, thereby suppressing overall leakage current.
Solution Approach 2:
The concentration of the second compound is localized to specific regions rather than being uniformly distributed. The second compound is present in high concentration in the first region where it efficiently generates charges upon light absorption, but is absent or present in low concentration in the second region where it would otherwise contribute to leakage current. This local quality control suppresses leakage current while maintaining charge generation efficiency.
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 suppresses leakage current, enhances detection sensitivity, and achieves high-speed response characteristics by optimizing the structure and composition of the organic layer, leading to improved photodetector performance.
Implementation Method 1
a photodetector includes a first conductive layer, a second conductive layer, and an organic layer provided between the first conductive layer and the second conductive layer
Data Source
AI summary
According to one embodiment, a photodetector includes a first conductive layer, a second conductive layer, and an organic layer provided between the first conductive layer and the second conductive layer. The organic layer includes a first region and a second region. The second region is provided between the first region and the second conductive layer. The first region includes a first compound and a second compound. The first compound includes a first mother skeleton. The second region includes the first compound and a third compound. The third compound includes the first mother skeleton. The third compound is different from the first compound. The second region does not include the second compound, or a concentration of the second compound in the second region is lower than a concentration of the second compound in the first region.