Indolocarbazole Material for High-Sensitivity Photoelectric Imaging
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Solution Overview
Problem
Existing photoelectric conversion devices for imaging applications, such as digital cameras and smartphone cameras, face challenges in achieving higher sensitivity and resolution, particularly due to inefficiencies in light utilization and pixel resolution, which are not adequately addressed by conventional inorganic semiconductor-based devices.
Innovation Solution
The use of an indolocarbazole compound with a specific carbazole structure as a substituent in the photoelectric conversion device, enhancing charge generation and movement, thereby improving the contrast ratio and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inorganic semiconductor-based photoelectric conversion devices use RGB color filters disposed on a plane, then color image acquisition is achieved, but light utilization efficiency decreases and resolution is limited
Solution Approach 1:
The patent transitions from planar disposition of RGB color filters to a three-dimensional stacked configuration of multiple photoelectric conversion devices with different spectral sensitivities. This vertical stacking in the third dimension enables simultaneous capture of multiple wavelength regions without lateral light blocking, thereby improving both resolution and light utilization efficiency
Solution Approach 2:
The invention divides the photoelectric conversion function into multiple separate devices stacked vertically, each optimized for specific wavelength regions (e.g., blue, green, red, or extended spectral regions). This segmentation allows each layer to independently process specific wavelengths without interference, improving overall spectral efficiency and resolution
2Measurement precision
If organic semiconductors are used to selectively absorb specific wavelength regions, then sensitivity for color imaging improves, but charge transport characteristics become insufficient
Solution Approach 1:
The patent employs composite material systems combining organic semiconductors with carefully engineered hole blocking layers and electron blocking layers. These composite structures leverage the wavelength-selective absorption of organic semiconductors while using the blocking layers to compensate for insufficient charge transport, creating a synergistic system that achieves both high sensitivity and reliable charge extraction
Solution Approach 2:
The invention introduces hole blocking layers and electron blocking layers as intermediary components between the organic photoelectric conversion layer and electrodes. These intermediary layers mediate charge transport by blocking minority carriers (holes at electron collecting electrode, electrons at hole collecting electrode) while allowing majority carriers to pass, thereby improving charge extraction efficiency without compromising the organic semiconductor's wavelength-selective absorption capability
3Productivity
If bias voltage is applied to accelerate charge separation and movement, then photoelectric conversion efficiency improves, but leakage current increases
Solution Approach 1:
The patent uses hole blocking layers and electron blocking layers as intermediary components that enable effective charge separation and extraction at lower bias voltages. These blocking layers prevent recombination and facilitate directional charge movement, maintaining high photoelectric conversion efficiency while reducing the need for high bias voltages that would otherwise generate excessive leakage current
Solution Approach 2:
The invention optimizes energy level parameters of the organic semiconductors and blocking layers to achieve efficient charge separation with minimal bias voltage. By carefully selecting materials with appropriate HOMO and LUMO levels, the system achieves effective charge extraction at low voltages, thereby improving photoelectric conversion efficiency while suppressing leakage current generation
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
This approach results in a photoelectric conversion device with reduced leakage current and high contrast ratio, achieving low dark current values and improved imaging performance.
Implementation Method 1
light having a desired wavelength is absorbed in the photoelectric conversion layer to generate an exciton, and then charge separation of the exciton generates a hole and an electron
Implementation Method 2
charge separation of the exciton generates a hole and an electron. Thereafter, the hole and the electron move toward each electrode
Data Source
AI summary
Provided are a material that achieves higher sensitivity and higher resolution of a photoelectric conversion device for imaging, and a photoelectric conversion device for imaging using the above material. A material for a photoelectric conversion device for imaging, the material including an indolocarbazole compound represented by the following general formula (1) and a photoelectric conversion device for imaging using the above material. In the general formula (1), the ring B is fused with an adjacent ring at any position, and represents a six-membered ring represented by the formula (1B). The ring C is fused with an adjacent ring at any position, and represents a five-membered ring represented by the formula (1C). At least one of Ar1 to Ar5 is represented by the following general formula (2) or the like. In the general formula (2), “*” represents a bonding point to the general formula (1).