Photoactive Compound for Near-Infrared Photodetection
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Solution Overview
Problem
Current organic photodetectors face limitations in absorbing light at long wavelengths, particularly in the near-infrared range, which hampers their efficiency in detecting light sources with peak wavelengths greater than 750 nm.
Innovation Solution
Development of a compound with formula (I) that can absorb light at long wavelengths, used in combination with an electron donor compound to form a photosensitive organic layer in organic photodetectors, enhancing their ability to detect near-infrared light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional organic photodetector materials are used, then the device structure is simple and manufacturing is easier, but the light absorption capability at long wavelengths (near-infrared range) is insufficient
Solution Approach 1:
The patent employs composite materials by combining a non-fullerene acceptor compound (formula I) with a conjugated copolymer donor in a bulk heterojunction configuration. This composite approach enables the material system to absorb light at long wavelengths (including near-infrared range) while maintaining processability and device functionality, directly resolving the contradiction between improved light absorption and material complexity
Solution Approach 2:
The patent utilizes parameter changes by modifying the molecular structure of the acceptor compound through variations in substituents (R1-R14 groups) and structural parameters (Y=O or S, Z1-Z4 bond configurations). These structural parameter changes enable tuning of the optical properties to achieve absorption at wavelengths greater than 750 nm, including near-infrared regions, while controlling the balance between absorption capability and material synthesizability
2Reliability
If conventional photodetector materials are used, then the external quantum efficiency is moderate, but the detection capability at wavelengths above 950 nm is limited
Solution Approach 1:
The patent applies parameter changes by optimizing the molecular parameters of the acceptor compound, including the choice of Y (O or S), the configuration of Z1-Z4 (direct bonds or aromatic groups), and the substituents R1-R14. These parameter variations enable the material to achieve high external quantum efficiency specifically at wavelengths above 950 nm, extending the detection wavelength range while maintaining high reliability performance
Solution Approach 2:
The patent implements local quality by designing the acceptor compound with specific local structural features (such as the CN groups at R11-R14, the Y=O or S carbonyl groups, and the aromatic/heteroaromatic Z1-Z4 regions) that are particularly effective for near-infrared absorption. These localized structural elements provide the necessary optical properties for high efficiency detection at long wavelengths without requiring the entire material system to be complex
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 enables organic photodetectors to achieve higher external quantum efficiencies compared to traditional systems, particularly at wavelengths above 950 nm, improving their performance in detecting near-infrared light.
Implementation Method 1
compounds of formula (I) may be capable of absorbing light at long wavelengths, e.g. greater than 750 nm, optionally greater than 950 nm
Data Source
AI summary
A compound of formula (I): Each R1 and R2 is, independently in each occurrence, a substituent. Each R3-R10 is, independently in each occurrence, H or a substituent. At least one occurrence of at least one of R11-R14 is CN. Each Y is independently O or S. Z1-Z4 are each independently a direct bond or Z1, Z2, Z3 and/or Z4 together with, respectively, R4 or R5, R7 or R8, R6, or R9 forms an aromatic or heteroaromatic group. The compound of formula (I) may be provided in an active layer of an organic electronic device, e.g. as an electron acceptor in a bulk heterojunction layer of an organic photodetector. A photosensor may comprise the organic photodetector and a light source, e.g. a near infra-red light source.