Organic Sensor Auxiliary Layer Energy Alignment
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Solution Overview
Problem
The sensitivity of silicon photodiodes in organic sensors is deteriorated due to reduced pixel size and absorption area, and the characteristics of organic materials used as alternatives are difficult to predict, making it challenging to control the properties of photoelectric conversion devices.
Innovation Solution
A device with a specific configuration of auxiliary layers and energy level alignments between the active layer, auxiliary layers, and electrodes is used to improve charge extraction characteristics by reducing residual charge carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If organic materials are used to replace silicon in photodiodes to maintain sensitivity with reduced pixel size, then the absorption area is increased, but the characteristics become difficult to predict and control due to high binding energy and recombination behavior
Solution Approach 1:
An auxiliary layer is introduced between the active layer and the electrode to mediate charge extraction. This auxiliary layer has specifically designed HOMO energy levels that facilitate efficient charge transport while reducing residual charge carriers, thereby improving device reliability and controllability without sacrificing the high absorption area provided by organic materials
Solution Approach 2:
The HOMO energy levels of the auxiliary layer are specifically engineered to be positioned between the active layer and the electrode, creating optimal energy alignment. This parameter change in energy level positioning enables controlled charge extraction and reduces the unpredictable recombination behavior of organic materials
2Measurement precision
If pixel size is reduced to achieve higher sensor resolution, then more pixels can be packed, but the sensitivity of silicon photodiodes deteriorates due to reduced absorption area
Solution Approach 1:
The patent uses organic materials as an alternative 'copy' or replacement for silicon photodiodes, leveraging their higher extinction coefficient and tunable absorption characteristics to achieve maintained or improved sensitivity even at reduced pixel sizes. The organic active layer can be designed to absorb specific wavelength ranges efficiently
Solution Approach 2:
The device employs a composite structure combining organic active layer with inorganic auxiliary layer and electrode materials. This composite approach leverages the high absorption coefficient of organic materials while using the auxiliary layer to manage charge extraction, achieving both high resolution and maintained sensitivity
3Reliability
If auxiliary layers are added to improve charge extraction efficiency, then residual charge carriers are reduced, but device structure becomes more complex
Solution Approach 1:
The device is segmented into distinct functional layers: the active layer for light absorption and the auxiliary layer for charge extraction. This segmentation allows each layer to be optimized independently - the active layer for high absorption and the auxiliary layer for efficient charge transport with controlled energy levels
Solution Approach 2:
The auxiliary layer serves as an intermediary between the active layer and electrode, specifically designed to facilitate charge extraction. By positioning its HOMO energy levels optimally, it acts as a mediator that reduces residual charge carriers without requiring complex multi-layer structures
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 proposed solution enhances the charge extraction efficiency, reduces residual charge carriers, and improves the electrical performance of the device, leading to better sensitivity and integration of the sensor.
Implementation Method 1
A photoelectric conversion device may receive incident light and convert the received incident light into an electrical signal
Data Source
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AI summary
A device includes a first electrode and a second electrode, an active layer between the first electrode and the second electrode and a plurality of auxiliary layers between the first electrode and the active layer. The auxiliary layers include first and second auxiliary layers, the first auxiliary layer proximate to the active layer, the second auxiliary layer proximate to the first electrode. An energy level of the active layer, an energy level of the first auxiliary layer, an energy level of the second auxiliary layer, and a work function of the first electrode become deeper sequentially or shallower sequentially.