Donor-Acceptor Photoactive Material for NIR Detection Beyond 1300 Nm
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Solution Overview
Problem
Current photoresponsive materials for organic electronic devices, particularly those used in photodetectors, face challenges in efficiently detecting light with wavelengths beyond 1100 nm due to limitations in absorption spectra and energy level alignment between electron donor and acceptor materials.
Innovation Solution
A material comprising an electron-accepting unit of a specific formula, which includes aromatic rings and electron-withdrawing groups, is combined with an electron-donating unit to form a bulk heterojunction layer in organic photoresponsive devices, enhancing absorption in the NIR range and optimizing energy levels for improved light detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photoresponsive materials are used, then device structure is simple, but light detection efficiency beyond 1100 nm is insufficient
Solution Approach 1:
The patent employs composite materials by combining electron-donating units (such as carbazole, fluorene) with electron-accepting units (such as isoindolo[2,1-a]benzimidazol-11-one, naphthalene benzimidazole) to create donor-acceptor conjugated copolymers. This composite structure enables enhanced light detection efficiency in the NIR range beyond 1100 nm through optimized energy level alignment and extended absorption spectra, while maintaining manageable device complexity through systematic molecular design.
2Reliability
If electron-accepting units with deepened LUMO levels are introduced, then NIR light detection efficiency is improved, but energy level alignment requirements become more stringent
Solution Approach 1:
The patent systematically modifies molecular parameters by introducing different electron-withdrawing groups (fluorine, cyano, carbonyl) at specific positions of the electron-accepting units to precisely tune the LUMO energy levels. This parameter optimization enables deepening of LUMO levels to improve NIR detection efficiency while maintaining appropriate energy level alignment with electron-donating units, thereby managing the complexity through controlled molecular design.
3Adaptability or versatility
If absorption spectra are extended to longer wavelengths, then detection range beyond 1300 nm is enhanced, but material stability may be compromised
Solution Approach 1:
The patent applies local quality by introducing electron-withdrawing groups at specific local positions (positions 5, 6, 7, or 8 of the naphthalene benzimidazole ring system) to extend absorption spectra to longer wavelengths for enhanced detection range. The localized modification of electron density distribution through these substituent groups enables wavelength extension while the overall conjugated backbone structure maintains material stability through preserved structural integrity.
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 material significantly enhances light detection efficiency in the NIR range, particularly beyond 1300 nm, by deepening the LUMO level of the electron-accepting unit and aligning it with the HOMO level of the electron-donating unit, leading to improved performance in organic photodetectors.
Implementation Method 1
enhancing absorption in the NIR range
Implementation Method 2
A material comprising an electron-accepting unit of a specific formula, which includes aromatic rings and electron-withdrawing groups, is combined with an electron-donating unit to form a bulk heterojunction layer in organic photoresponsive devices
Data Source
AI summary
A material comprising an electron-accepting unit of formula (I): Ar is an aromatic ring; Ar1 is a substituted or unsubstituted 5- or 6-membered heteroaromatic ring containing N and C ring atoms; when Ar1 is a substituted or unsubstituted 6-membered heteroaromatic ring, Ar2 is a substituted or unsubstituted 6-membered heteroaromatic ring wherein the ring atoms are selected from N and C; when Ar1 is a 5-membered heteroaromatic ring, Ar2 is a substituted or unsubstituted 5- or 6-membered heteroaromatic ring; Ar3 is a 5-membered ring or a substituted or unsubstituted 6-membered ring; Ar4 is a 5-membered ring or a substituted or unsubstituted 6-membered ring or is absent; Ar5 is a substituted or unsubstituted monocyclic or polycyclic group containing at least one aromatic or heteroaromatic ring; Ar6 is a substituted or unsubstituted monocyclic or polycyclic group containing at least one aromatic or heteroaromatic ring or is absent; and each X is independently a substituent bound to a C atom of Ar3, and where present Ar4, with the proviso that at least one X is an electron withdrawing group; and wherein the material further comprises an electron-donating unit.