Organic Solar Cell Absorber Layer System for Efficiency

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Solution Overview

Problem

Organic solar cells face efficiency limitations due to poor transport properties of organic semiconductors, leading to low energy conversion efficiencies, especially in large-area applications, where achieving 10% efficiency is necessary but challenging with current tandem cell structures.

Innovation Solution

A photoactive component with a tandem or multiple cell structure featuring a photoactive acceptor-donor layer system using at least three absorber materials, where two absorber materials are partially present in a mixed layer, with one material having a narrower absorption range and higher optical density, allowing for broader absorption and higher open-circuit voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional organic solar cell structures with limited absorber materials are used, then device complexity is low, but energy conversion efficiency remains below 10%

Engineering Contradiction:
Improveenergy conversion efficiencyVSAvoidcomplexity of absorber layer system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines multiple absorber materials (at least three different materials) into a single integrated photoactive acceptor-donor layer system. This merging approach allows the system to absorb a broader spectrum of light simultaneously, achieving energy conversion efficiencies of 10% or higher while maintaining a relatively simple overall device structure with just two electrodes and the photoactive layer between them.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention uses composite material systems comprising multiple organic absorber materials with different absorption characteristics. These composite absorber layers are designed to complement each other's spectral absorption, creating a synergistic effect that broadens the overall light absorption range and increases energy conversion efficiency without requiring complex device architectures.

Inventive Principle:
Principle #40Composite materials

2Productivity

If the absorption range of absorber materials is broadened to capture more light, then energy conversion efficiency improves, but open-circuit voltage decreases due to reduced energy per photon

Engineering Contradiction:
Improveenergy conversion efficiencyVSAvoidopen-circuit voltage
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The patent applies local quality by assigning different functional roles to different absorber materials within the photoactive layer. Each absorber material is selected with specific absorption characteristics optimized for particular wavelength ranges. The system strategically positions materials with narrow absorption ranges and high optical density to maintain high open-circuit voltage, while other materials with broader absorption contribute to overall efficiency, creating a spatial and functional differentiation that resolves the voltage-efficiency trade-off.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention optimizes key parameters of the absorber materials, particularly the balance between absorption range and optical density. By carefully selecting and tuning the optical density of materials with narrower absorption ranges, the system maintains high open-circuit voltage while still achieving broad overall absorption through the combination of multiple materials. This parameter optimization allows simultaneous improvement of both voltage and efficiency.

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

This configuration enhances the open-circuit voltage and overall efficiency of organic solar cells, enabling them to reach 10% or higher efficiency by optimizing the absorption range and optical density of absorber materials, thereby improving energy conversion efficiency.

Implementation Method 1

The light incident through the transparent base contact generates excitons (bound electron-hole pairs) in the i-layer or in the n-/p-layer

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

A solar cell converts light energy into electrical energy

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP2385556B1Photoactive device with organic layers
Publication Date: 2021.01.20 HELIATEK GMBH
  • EP2385556B1 patent drawingFigure 1~3
  • EP2385556B1 patent drawingFigure 4~6
  • EP2385556B1 patent drawingFigure 7~9

AI summary

The component has single, tandem or multiple solar cells with two electrodes (12, 17), and a photoactive acceptor-donor layer system e.g. hole transport layer (HTL) or electron transport layer (ETL) system (13), arranged between the electrodes, where the layer system has three absorber materials. Two of the absorber materials are formed as donors or acceptors, where one of the two absorber materials is configured as donor or acceptor to absorb light at greater wavelengths than the other material and has a lower stokes-shift and/or lower absorption width than the other material.