Organic Solar Cell Photoactive Layer Composition

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Solution Overview

Problem

Organic solar cells face efficiency and stability challenges due to charge loss from electron and hole recombination, often requiring additional processing steps that increase manufacturing costs.

Innovation Solution

A photoactive layer comprising a higher content of single molecular material than polymer material, with a specific weight ratio, is used in an organic solar cell, incorporating a copolymer with a defined molecular weight range and electron acceptor, enhancing efficiency and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If additional processes are introduced to deliver charges to electrode without loss, then charge loss is reduced, but manufacturing cost increases

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

Solution Approach 1:

The patent changes the chemical composition parameters of the photoactive layer by incorporating a polymer material with specific functional groups (cyano, carbonyl, ester, or amide groups) to modify the energy levels and charge transport properties. This compositional parameter change enables efficient charge delivery without requiring additional processing steps, thus reducing charge loss while maintaining ease of manufacture

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite photoactive layer by combining a polymer material with specific electron-accepting functional groups with other organic semiconductor materials. This composite structure provides both efficient charge transport and simple processing characteristics, resolving the contradiction between reducing charge loss and maintaining manufacturing simplicity

Inventive Principle:
Principle #40Composite materials

2Productivity

If inorganic solar cells are used, then power conversion efficiency reaches approximately 24%, but economic feasibility and material availability are limited

Engineering Contradiction:
Improvepower conversion efficiencyVSAvoideconomic feasibility
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent employs organic semiconductor materials that are inexpensive, abundant, and easily processed compared to inorganic materials like crystalline silicon. The polymer-based photoactive layer can be manufactured through simple solution processing techniques, making the solar cell economically feasible while achieving competitive power conversion efficiency through optimized molecular design and composition

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If polymer material is used as electron donor, then efficiency is improved, but processability may be compromised

Engineering Contradiction:
ImproveefficiencyVSAvoidprocessability
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent optimizes the molecular weight parameter of the polymer material to balance efficiency and processability. By selecting an appropriate molecular weight range, the polymer achieves sufficient charge transport capability for high efficiency while maintaining solubility and processability for simple manufacturing. The specific functional groups on the polymer chain also tune the energy levels to match with electron acceptors, enhancing efficiency without compromising processability

Inventive Principle:
Principle #35Parameter changes

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 approach results in improved efficiency and stability of organic solar cells by optimizing the ratio of single molecular material to polymer material in the photoactive layer, reducing charge loss and manufacturing complexity.

Implementation Method 1

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

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP3557642B1Photoactive layer and organic solar cell including same
Publication Date: 2022.01.05 LG CHEM LTD
  • EP3557642B1 patent drawingFigure 1~2
  • EP3557642B1 patent drawingFigure 3~4
  • EP3557642B1 patent drawingFigure 5~6

AI summary

The present specification provides a photoactive layer including: an electron donor; and an electron acceptor, in which the electron donor includes: a single molecular material; and a polymer material, a content of the electron donor is higher than a content of the electron acceptor, and in the electron donor, a content of the single molecular material is higher than a content of the polymer material, and an organic solar cell including the same.