Multi-Component Polymer for Organic Solar Cells
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Solution Overview
Problem
Organic photovoltaic cells exhibit low quantum yield and conversion efficiency due to the second-order nature of their intrinsic photoconductive process, requiring a trade-off between thick, resistive cells with multiple interfaces and thin, low optical absorption efficiency cells.
Innovation Solution
A multi-component benzo[1,2-B:4,5-B] dithiophene-difluorothienothiophene polymer with two different sets of repeat units, where R1, R2, R3, and R4 are independently selected from alkyl, alkoxy, and aryl groups, and the introduction of fluorine atoms to lower the HOMO energy level, enhancing charge transport and 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 modifies the chemical composition and molecular structure of the active layer materials, specifically using conjugated polymers with optimized HOMO-LUMO energy levels to enhance exciton generation and charge separation efficiency, thereby improving quantum yield without increasing cell thickness
Solution Approach 2:
The patent employs composite active layer structures combining conjugated polymers with appropriate electron acceptors or donors, creating optimized material systems that simultaneously achieve high optical absorption and high charge separation efficiency, resolving the trade-off between thickness and quantum yield
2Use of energy by moving object
If the cell thickness is increased to improve optical absorption, then the optical absorption efficiency is improved, but the electrical resistance increases
Solution Approach 1:
The patent optimizes the electrical properties of the active layer by selecting conjugated polymers with appropriate charge carrier mobility and energy level alignment, enabling efficient charge transport in thinner films and reducing electrical resistance while maintaining optical absorption
Solution Approach 2:
The patent introduces multiple interfaces and folded structures within the active layer to increase the effective optical path length without increasing the physical thickness of the cell, thereby maintaining low electrical resistance while improving optical absorption
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 polymer demonstrates increased solar conversion efficiency, elevated open circuit voltage, and improved short circuit current and fill factor, making it suitable for use in photovoltaic devices such as solar cells and photodetectors.
Implementation Method 1
Solar energy using photovoltaic effect requires active semiconducting materials to convert light into electricity
Data Source
AI summary
A polymer having two different sets of repeat units consisting essentially of:In this polymer, R1, R2, R3 and R4 can be independently selected from the group consisting of alkyl group, alkoxy group, aryl groups and combinations thereof. Also the combination of R1, R2, R3 and R4 are not all identical and n and o are greater than 1.