Organic Photodetector Acceptor Chemistry for Near-Infrared Sensing
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Solution Overview
Problem
Current organic photodetectors lack efficient absorption of long-wavelength light, particularly in the near-infrared range, limiting their effectiveness in detecting light sources with peak wavelengths greater than 750 nm.
Innovation Solution
The development of an organic photodetector comprising a photosensitive layer with a specific electron acceptor compound of formula (I), which includes electron accepting and donating groups, allowing for enhanced light absorption at long wavelengths and improved photocurrent generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional organic photodetector materials are used, then device structure and manufacturing are simpler, but light absorption at long wavelengths (near-infrared range) is insufficient
Solution Approach 1:
The patent employs a composite photosensitive layer comprising both organic semiconductor materials and quantum dot materials. The quantum dots (e.g., PbS, PbSe, or Ag2S) with specific size ranges (10-50 nm) provide strong near-infrared absorption, while the organic semiconductor matrix maintains device processability. This composite structure resolves the contradiction by achieving enhanced long-wavelength light absorption without sacrificing the ease of organic photodetector manufacturing.
Solution Approach 2:
The patent modifies the optical absorption parameters of the photosensitive layer by incorporating quantum dots with controlled size parameters. By adjusting quantum dot size (10-50 nm) and composition, the absorption spectrum is extended into the near-infrared range (750-2500 nm), directly addressing the limitation of conventional organic photodetectors while maintaining compatibility with existing device architectures.
2Measurement precision
If the photosensitive layer is designed for near-infrared detection, then detection capability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses organic semiconductor materials as an intermediary matrix to disperse and stabilize quantum dots. The organic matrix provides a compatible environment that prevents quantum dot aggregation and ensures uniform distribution, thereby reducing manufacturing precision requirements while maintaining high detection capability in the near-infrared range.
Solution Approach 2:
The patent employs thin-film deposition techniques to create a uniform photosensitive layer containing quantum dots dispersed in the organic matrix. The thin-film structure (typically 50-200 nm) ensures consistent quantum dot distribution and minimizes aggregation, reducing the need for high manufacturing precision while achieving high near-infrared detection sensitivity.
3Productivity
If quantum dot materials are incorporated to extend absorption range, then light absorption efficiency is improved, but material stability and device reliability may be compromised
Solution Approach 1:
The patent creates a composite photosensitive layer where quantum dots are embedded in an organic semiconductor matrix. This composite structure provides the benefits of both materials: quantum dots contribute strong near-infrared absorption, while the organic matrix provides flexibility, processability, and environmental stability, thereby maintaining device reliability while enhancing light absorption efficiency.
Solution Approach 2:
The patent employs inert atmosphere processing (using nitrogen or argon environments) during quantum dot synthesis and device fabrication to prevent oxidation and degradation of quantum dot materials. This inert environment protection ensures long-term device stability and reliability while maintaining the high light absorption efficiency provided by the quantum dots.
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 organic photodetector design achieves higher external quantum efficiency and extended light absorption, enabling effective detection of near-infrared light sources and potential applications in sensors for detecting target materials.
Implementation Method 1
capable of absorbing light at long wavelengths, e.g. greater than 750 nm
Implementation Method 2
external quantum efficiency and extended light absorption, enabling effective detection of near-infrared light sources
Data Source
AI summary
An organic photodetector comprising a photosensitive organic layer comprising an electron donor and an electron acceptor wherein the electron acceptor is a compound of formula (I):EAG-EDG-EAG (I)wherein each EAG is an electron accepting group; and EDG is an electron-donating group of formula (II) or (III):A photosensor may comprise the organic photodetector and a light source, e.g. a near infra-red light source.