A-D-A'-D-A Nonfullerene Acceptors for Extended Light Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current electron-accepting non-fullerene compounds for photoresponsive devices face limitations in achieving optimal performance, particularly in terms of absorption peaks and energy level alignment, which affects the efficiency of organic solar cells and photodetectors.
Innovation Solution
Development of a compound with a specific formula (I) comprising electron-donating and electron-accepting groups, where the electron-accepting groups have deeper lowest unoccupied molecular orbital (LUMO) levels, and the use of bridging groups to optimize energy level alignment and absorption spectra, particularly extending absorption peaks beyond 900 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional electron-accepting non-fullerene compounds are used, then device structure is simpler, but absorption peak wavelength is limited (cannot extend beyond 900 nm)
Solution Approach 1:
The molecule is divided into distinct functional segments: electron-donating groups (D1, D2), electron-accepting groups (A1, A2, A3), and bridging groups (B1, B2). This segmentation allows independent optimization of each segment's properties to achieve extended absorption while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The patent creates a composite molecular structure combining multiple electron-donating and electron-accepting units with bridging groups to form a Donor-Acceptor-Donor type compound. This composite approach enables synergistic effects that extend absorption peaks beyond 900 nm while distributing structural complexity across multiple functional components.
2Reliability
If electron-accepting groups with deeper LUMO levels are used, then energy level alignment is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by positioning specific electron-accepting groups (A1, A2, A3) with tailored LUMO levels at different locations within the molecular structure. Each group is optimized for its specific role in energy level alignment, allowing precise control over electron transfer processes while using established synthetic methods for each functional unit.
Solution Approach 2:
The patent systematically varies key molecular parameters including LUMO energy levels of electron-accepting groups, HOMO energy levels of electron-donating groups, and the nature of bridging groups to optimize energy level alignment. These parameter adjustments are achieved through controlled chemical modifications using standard organic synthesis techniques.
3Use of energy by moving object
If a-d-a'-d-a type compound structure is used, then light absorption at longer wavelengths is enhanced, but device fabrication complexity increases
Solution Approach 1:
The patent introduces dynamic character through the alternating Donor-Acceptor-Donor arrangement where electron density can dynamically redistribute upon light absorption. The a-d-a'-d-a structure enables flexible electron-hole separation and transport pathways, enhancing light energy utilization while the modular nature keeps structural complexity manageable.
Solution Approach 2:
The patent extends the molecular structure into multiple dimensions by creating a five-unit alternating sequence (A-D-A'-D-A) with spatially distributed electron-donating and electron-accepting groups. This multi-dimensional arrangement creates multiple pathways for charge separation and enhances absorption cross-section without requiring excessively large molecular sizes.
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 enhances the absorption of light at longer wavelengths, improving the performance of organic photodetectors and solar cells by increasing the absorption peak beyond 900 nm and optimizing energy level alignment, leading to enhanced external quantum efficiency and current density.
Implementation Method 1
the compound enhances the absorption of light at longer wavelengths, improving the performance of organic photodetectors and solar cells by increasing the absorption peak beyond 900 nm
Data Source
AI summary
A compound of formula (I), D1 and D2 are electron-donating groups; A2 and A3 are electron-accepting groups; B1 and B2 are bridging groups; x1 and x2 are 0, 1, 2 or 3; y1 and y2 are at least 1; z1 and z2 are 0, 1, 2 or 3; and A1 is a group of formula (II) wherein Ar1 is an aromatic or heteroaromatic group; and Y is O, S, NR4 or R1-C═C—R1 wherein R1 in each occurrence is independently H or a substituent wherein two substituents R1 may be linked to form a monocyclic or polycyclic ring and R4 is H or a substituent. The compound may be used as an electron-accepting material with an electron-donating material in an organic photodetector.