Quinoxaline-Based Polymer Solar Cell Absorption
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Solution Overview
Problem
Organic thin-film solar cells have low conversion efficiencies and short working lifetimes due to limited absorption spectrum width of p-type semiconductor polymers, which restricts their photoelectric conversion efficiency.
Innovation Solution
Development of an organic compound with a polymer structure comprising a repeating unit that includes a quinoxaline skeleton as the acceptor and a donor structure, expanding the absorption spectrum width and improving carrier mobility, thereby enhancing photoelectric conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional p-type semiconductor polymers are used in organic thin-film solar cells, then the device structure can be maintained, but the absorption spectrum width is limited and conversion efficiency remains low
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of the p-type semiconductor polymer. Specifically, it introduces a quinoxaline skeleton as the acceptor unit and combines it with various donor structures (thiophene, selenophene, carbazole, fluorene, etc.) to create polymers with deepened HOMO levels and broadened absorption spectra. This structural parameter change enables the polymer to absorb light across a wider wavelength range and achieve higher conversion efficiencies of up to 3.43%
Solution Approach 2:
The patent employs composite materials by creating copolymer structures that combine different functional units. The quinoxaline-based acceptor unit is polymerized with various donor monomers to form composite polymer structures. These composite structures integrate the electron-accepting properties of quinoxaline with the light-absorbing and hole-transporting capabilities of different donor groups, resulting in materials with superior photoelectric conversion performance compared to homopolymers
2Reliability
If the absorption spectrum width is expanded to improve photoelectric conversion efficiency, then conversion efficiency increases, but the HOMO level must be deepened which complicates material design
Solution Approach 1:
The patent systematically changes molecular parameters by selecting specific donor units with appropriate HOMO levels to pair with the quinoxaline acceptor. By choosing donors such as thiophene, selenophene, carbazole, and fluorene with varying electronic properties, the patent achieves deepened HOMO levels (improving stability and open-circuit voltage) while maintaining or expanding absorption spectrum width, thus resolving the complexity issue through targeted parameter optimization
3Ease of manufacture
If organic thin-film solar cells are produced by non-vacuum processes, then mass production at low cost is enabled, but conversion efficiency and working lifetime are inferior to conventional solar cells
Solution Approach 1:
The patent changes the material parameters by developing p-type semiconductor polymers with inherently superior properties (deepened HOMO levels, broadened absorption spectra, improved carrier mobility) that enable high conversion efficiencies even when processed by simple non-vacuum coating methods. The quinoxaline-based polymers achieve efficiencies of up to 3.43% through solution processing, demonstrating that material optimization can compensate for process simplicity
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 organic compound with a deepened HOMO level and broadened absorption spectrum achieves higher photoelectric conversion efficiency, surpassing conventional p-type semiconductors like PCDTBT and PTB7, with a measured conversion efficiency of up to 3.43% in organic thin-film solar cells.
Implementation Method 1
The photoelectric conversion process in an organic thin-film solar cell is said to undergo the following steps: (1) light absorption and exciton generation by organic molecules
Data Source
AI summary
Embodiments of the present invention provide an organic semiconductor excellent in the photoelectric conversion efficiency and also a solar cell using the same. This organic semiconductor has a polymer structure comprising a repeating unit represented by the following formula (I): -[A-D]- (I). In the formula, A is a structure represented byand D is a structure having a benzodithiophene skeleton or the like. In the above, R1 is independently H, a substituted or unsubstituted straight-chain or branched-chain alkyl group, or a substituted or unsubstituted straight-chain or branched-chain alkoxy group. The solar cell according to an embodiment of the present invention comprises an active layer containing the organic semiconductor.