All-Solution-Processed Interconnection Layer for Tandem Organic Solar Cells

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Solution Overview

Problem

Multi-junction organic tandem solar cells face challenges in achieving high power conversion efficiency due to the complexity of fabricating interconnection layers, particularly with non-fullerene materials, which require additives or thin metal layers, limiting their performance and stability.

Innovation Solution

An all-solution-processed interconnection layer is developed using a hole-transporting sub-layer formed from an aqueous poly(3,4-ethylenedioxythiophene) polystyrene sulfonate dispersion, allowing for simple solution casting and low-temperature annealing, enhancing the optical absorption range and power conversion efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional interconnection layers are used with non-fullerene materials, then charge transport is achieved, but manufacturing complexity increases due to requiring additives or thin metal layers

Engineering Contradiction:

Improveinterconnection layer fabricationVSAvoidinterconnection layer structure

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the need for additives and thin metal layers from the interconnection layer structure by using a pure PEDOT:PSS polymer coating. This removes the complex multi-component system down to a single polymer material that achieves the same charge transport function without requiring additional processing steps for additive management or metal layer deposition.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the material parameter from composite systems (non-fullerene acceptors with additives) to a pure polymer system (PEDOT:PSS). This parameter change simplifies the interconnection layer composition while maintaining charge transport capability, eliminating the need for complex additive formulations and thin metal layer stackups.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional interconnection methods are used, then electrical connection is established, but power conversion efficiency is limited at 17% or below

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidfabrication process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the interconnection layer into distinct functional sub-layers: a hole-transporting sub-layer and an electron-transporting sub-layer. This segmentation allows each sub-layer to be optimized for its specific charge transport function, achieving superior overall device performance and power conversion efficiency exceeding 17% while maintaining solution-processability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite material design by combining PEDOT:PSS polymer with specific additives or configuring it in multi-sub-layer structures. This composite approach enhances charge transport properties and achieves power conversion efficiency exceeding 17%, overcoming the limitations of conventional single-material interconnection layers.

Inventive Principle:

Principle #40Composite materials

3Reliability

If multiple sub-layers are formed for improved performance, then power conversion efficiency increases to 25%, but manufacturing steps increase

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidfabrication speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges multiple coating steps into a unified solution-processing approach where the hole-transporting and electron-transporting sub-layers are both deposited using solution casting or spin-coating from liquid precursors. This merging of deposition methods maintains high productivity through simple solution processing while achieving the performance benefits of multi-sub-layer architecture with power conversion efficiency exceeding 25%.

Inventive Principle:

Principle #5Merging (Combining)

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 approach results in a power conversion efficiency exceeding 17%, up to 25%, by improving the wetting properties and charge extraction of the interconnection layer, facilitating the formation of multiple layers with reduced complexity and cost.

Implementation Method 1

forming a coating of an aqueous poly(3,4-ethylenedioxythiophene) polystyrene sulfonate dispersion liquid on a sub-cell surface of a multi-junction tandem organic solar cell

Methodology Applied

Scientific EffectSolution casting:

Implementation Method 2

drying the coating to form a hole-transporting sub-layer of an interconnection layer

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

improving the wetting properties and charge extraction of the interconnection layer

Methodology Applied

Scientific EffectWetting: Wetting

Implementation Method 4

allowing for simple solution casting and low-temperature annealing

Methodology Applied

Scientific EffectAnnealing: Annealing

Data Source

PatentUS20220140268A1Method of manufacturing all-solution-processed interconnection layer for multi-junction tandem organic solar cell

Publication Date: 2022.05.05 NEXTGEN NANO LLC

AI summary

A method of fabricating an all-solution-processed interconnection layer of a multi-junction tandem organic solar cell includes forming a coating of an aqueous poly(3,4-ethylenedioxythiophene) polystyrene sulfonate dispersion liquid on a sub-cell surface of a multi-junction tandem organic solar cell.