Organic Compound for Green Light Absorption in Image Sensors
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Solution Overview
Problem
Silicon photodiodes in image sensors face sensitivity issues due to their small absorption area, leading to a need for alternative materials that can enhance light absorption and thermal stability, particularly in the green wavelength range.
Innovation Solution
A compound with specific chemical properties, represented by Chemical Formula 1, is developed to selectively absorb light in the green wavelength range, featuring excellent light absorption characteristics and thermal stability, used in a photoelectric device configuration within image sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon photodiode is used in image sensor, then device structure is simple and manufacturing is mature, but light absorption area is small and sensitivity is deteriorated
Solution Approach 1:
The patent changes the material parameter from silicon to organic compound, specifically designing compounds with optimized molecular structures (Chemical Formulas 1-3) that exhibit enhanced light absorption coefficients and extended absorption spectra into the green wavelength range, thereby improving sensitivity while maintaining manufacturability through solution processing
Solution Approach 2:
The patent employs composite material strategies by combining organic compounds with specific functional groups (electron-accepting groups like fluorenone, dibenzofuranone with electron-donating groups) to create materials that simultaneously achieve high light absorption, thermal stability, and solution processability, resolving the contradiction between performance and manufacturing
2Measurement precision
If pixel size is reduced for high resolution, then image quality is improved, but absorption area is reduced and sensitivity deteriorates
Solution Approach 1:
The patent changes the optical parameter of the photodiode material by introducing organic compounds with high molar extinction coefficients (ε > 10,000 cm⁻¹M⁻¹) and optimized HOMO-LUMO energy gaps that absorb green light (500-560 nm), enabling small pixels to maintain high sensitivity through enhanced material-level light absorption rather than relying on large geometric area
Solution Approach 2:
The patent applies local quality optimization by designing organic compounds with specific molecular structures (Chemical Formulas 1-3) that concentrate light absorption capability at the molecular level, allowing each pixel element to maximize its light harvesting efficiency regardless of its small physical size
3Reliability
If organic material is used to replace silicon photodiode, then light absorption and integration are improved, but thermal stability under high temperature conditions is challenging
Solution Approach 1:
The patent changes the thermal parameter of organic materials by designing compounds with high glass transition temperatures (Tg > 100°C) and stable molecular structures (Chemical Formulas 1-3) that resist degradation during high-temperature manufacturing processes, thereby achieving both high light absorption efficiency and thermal stability
Solution Approach 2:
The patent uses composite material design by incorporating rigid structural units (fluorenone, dibenzofuranone) with flexible alkyl chains to create organic compounds that combine high light absorption with enhanced thermal stability, allowing the material to maintain its optical properties under high-temperature conditions
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 compound improves light absorption efficiency in the green wavelength range even under high temperature conditions, enhancing the performance of image sensors and electronic devices by selectively absorbing light and maintaining stability.
Implementation Method 1
A photoelectric device may convert light into an electrical signal using photoelectric effects
Data Source
AI summary
A compound represented by Chemical Formula 1 is provided. The compound has a reorganization energy of less than about 0.191 eV and a maximum absorption wavelength value calculated by density functional theory (DFT) of less than or equal to about 500 nm.In Chemical Formula 1, the definition of each group is as described in the specification.