Randomly Substituted Conjugated Polymers for Organic Solar Cells
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Solution Overview
Problem
Organic photovoltaic cells face low quantum yield due to the second-order nature of their intrinsic photoconductive process, resulting in a tradeoff between thick, resistive cells with multiple interfaces and thin, low optical absorption efficiency cells.
Innovation Solution
A process of polymerizing three-component benzo[1,2-b:4,5-b]dithiophene-thienothiophene randomly substituted polymers using specific stoichiometric ratios and polymerization reactions such as Stille Coupling, Suzuki Coupling, or Nickel Catalyzed reactions to produce conjugated polymers with optimized molecular weight and substituents for improved solar conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the cell thickness is increased to improve optical absorption efficiency, then the optical absorption efficiency is improved, but the electrical resistance increases and quantum yield decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer by incorporating electron-deficient units (such as benzothiadiazole, quinoxaline, or pyridine) into the conjugated polymer backbone. This modifies the HOMO-LUMO energy levels and bandgap of the polymer, enabling better energy alignment with the acceptor material and improved exciton dissociation efficiency, thereby resolving the contradiction between optical absorption and quantum yield
Solution Approach 2:
The patent creates a composite polymer structure by combining electron-rich units (donors) and electron-deficient units (acceptors) within the same polymer chain to form donor-acceptor conjugated polymers. This composite approach allows the polymer to simultaneously achieve high optical absorption through extended conjugation and high quantum yield through internal charge transfer complexes that facilitate exciton dissociation
2Reliability
If the cell thickness is decreased to reduce electrical resistance, then the quantum yield is improved, but the optical absorption efficiency decreases
Solution Approach 1:
The patent optimizes the bandgap parameter of the polymer by selecting specific electron-deficient units with appropriate electron-withdrawing strengths. This tuning allows the polymer to absorb light more efficiently in the visible spectrum while maintaining thin-film morphology that facilitates charge transport, thus achieving both high quantum yield and high optical absorption in thin cells
Solution Approach 2:
The patent introduces local electron-deficient sites within the polymer chain at specific positions (such as at the 2,5-positions of thiophene rings or through side-chain engineering). These local electron-deficient regions create favorable local electric fields that promote exciton dissociation and charge separation, improving quantum yield without requiring increased cell thickness
3Use of energy by moving object
If multiple interfaces or highly folded interfaces are introduced to improve optical absorption in thick cells, then the optical absorption efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent changes the optical parameters of the polymer by incorporating electron-deficient units that extend the absorption spectrum into the near-infrared region. This parameter change allows the polymer to absorb more photons per unit thickness, enabling high optical absorption efficiency in simple planar thin-film structures without requiring complex folded or multi-interface geometries
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 process enhances the solar conversion efficiency of organic photovoltaic cells by producing polymers with suitable molecular weight and substituents, leading to improved photovoltaic performance and film-forming properties.
Implementation Method 1
A process of polymerizing f with g and h wherein the stoichiometric ratio of f≈(g+h) and f, g and h are not equal to 0
Implementation Method 2
Conjugated polymers are polymers containing π-electron conjugated units along the main chain. The conjugated polymers have a 6-bond backbone of intersecting sp2 hybrid orbitals. The pz orbitals on the carbon atoms overlap with neighboring pz orbitals to provide π-bonds. The electrons that comprise the π-bonds are delocalized over the whole molecule.
Implementation Method 3
Solar energy using photovoltaic effect requires active semiconducting materials to convert light into electricity
Data Source
AI summary
A process of polymerizingf withwherein the stoichiometric ratio of f≈(g+h) and f, g and h are not equal to 0.This process can also have R1 selected from the group consisting of alkyl group, alkoxy group, aryl groups and combinations thereof. Additionally, x and y can be different from each other and can be independently selected from the group consisting of: alkyl group, alkoxy group, aryl groups,where y=1-3,where y=0-12,where R2 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups,where R3 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups,where R4 and R5 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, —NR6R7 where R6 and R7 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups.