Polymer for Organic Solar Cells Reducing Charge Recombination

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Solution Overview

Problem

Existing organic solar cells face challenges in maximizing power conversion efficiency due to charge loss from electron and hole recombination, which often requires additional processes increasing manufacturing costs.

Innovation Solution

A polymer comprising specific units represented by Chemical Formulae 1 and 2, with adjustable ratios to optimize solubility and energy levels, is used in an organic solar cell structure to enhance short-circuit current and reduce manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If additional processes are used to deliver electrons and holes to electrodes without loss, then charge loss due to recombination is reduced, but manufacturing costs increase

Engineering Contradiction:
Improvecharge lossVSAvoidmanufacturing cost
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The polymer material is designed to intrinsically facilitate charge transport to electrodes through its molecular structure and energy level configuration, eliminating the need for additional external processes. The material self-regulates charge delivery by optimizing electron and hole transport pathways, reducing recombination losses without requiring complex manufacturing steps or additional components.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention optimizes the energy levels (HOMO and LUMO) of the polymer material to specific ranges that enable efficient charge separation and transport. By adjusting these energy parameters, the material naturally directs electrons and holes toward respective electrodes with minimal recombination, achieving low charge loss without additional processes.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If polymer solubility is improved for easier processing, then manufacturing cost and time are reduced, but energy level optimization for high efficiency may be compromised

Engineering Contradiction:
ImprovesolubilityVSAvoidpower conversion efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The polymer incorporates specific chemical units (such as thiophene derivatives and electron-deficient units) that create a composite molecular structure. This structure simultaneously provides good solubility in common organic solvents for easy processing and maintains optimized energy levels for high power conversion efficiency, resolving the contradiction between manufacturability and performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The polymer chain contains different functional units with specialized roles: some units provide solubility through appropriate side chains and molecular weight control, while other units optimize energy levels for charge transport. This local differentiation of material properties within the polymer structure allows both good solubility and high efficiency to coexist.

Inventive Principle:
Principle #3Local quality

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 achieves high power conversion efficiency with improved solubility and reduced costs, maintaining a high short-circuit current and optimizing energy levels for efficient charge transport.

Implementation Method 1

An organic solar cell is a device that may directly convert solar energy into electric energy by applying a photovoltaic effect

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP3269753B1Polymer and organic solar cell comprising same
Publication Date: 2021.09.29 LG CHEM LTD
  • EP3269753B1 patent drawingFigure 1~2
  • EP3269753B1 patent drawingFigure 3~4
  • EP3269753B1 patent drawingFigure 5~6

AI summary

The present specification relates to a polymer and an organic solar cell including the same.