Stable N-Dopant Compounds for Solar Cell Electron Transport Layers

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Solution Overview

Problem

Existing organic solar cells face challenges with n-dopants that degrade easily due to atmospheric oxygen and lack air stability, and there are few compounds that can efficiently dope low LUMO compounds like fullerenes, leading to inefficiencies and stability issues in doped layers.

Innovation Solution

The development of a compound with the formula A-B, where A and B are arylene or arene skeletons, optionally substituted, and R groups are selected to form a stable n-dopant that can be used to increase conductivity and thermal stability of electron transport layers in solar cells, allowing for high conductivities and easy processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional n-dopants are used to dope electron transport layers, then conductivity is improved, but air stability deteriorates due to easy degradation by atmospheric oxygen

Engineering Contradiction:
Improveair stabilityVSAvoidprocessing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces an intermediary compound (compound 1) that acts as a stable n-dopant, mediating between the electron transport layer and atmospheric oxygen. This compound has a specific molecular structure with electron-donating groups that provide stability while maintaining doping functionality, thus resolving the contradiction between conductivity improvement and air stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical parameters of the dopant by using compound 1 with specific structural characteristics (electron-donating groups, aromatic rings) instead of conventional dopants. This parameter change results in both improved conductivity and enhanced air stability, as the new compound resists oxidation while effectively doping the electron transport layer.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If high doping concentration is used to achieve high conductivity, then electrical performance is improved, but thermal stability deteriorates

Engineering Contradiction:
ImproveconductivityVSAvoidthermal stability
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent optimizes the doping concentration parameter to a specific range (5-20 wt%) where both conductivity and thermal stability are maximized. Compound 1 enables high conductivity (up to 1 S/cm) at moderate doping levels, avoiding the thermal degradation issues associated with high doping concentrations while maintaining excellent electrical performance.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multiple doping attempts are made to achieve desired conductivity, then conductivity is improved, but processing time and complexity increase

Engineering Contradiction:
ImproveconductivityVSAvoidprocessing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent employs preliminary action by pre-synthesizing compound 1 with optimized doping properties before the actual device fabrication. This pre-prepared dopant can be directly incorporated into the electron transport layer in a single processing step, achieving desired conductivity without multiple iterative doping attempts, thus significantly improving processing efficiency.

Inventive Principle:
Principle #10Preliminary action

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 compound achieves conductivities of 1 S/cm with a doping concentration of 10 mol%, enhances thermal stability, and can be processed under various conditions, including vacuum and inert atmospheres, forming stable n-doped layers with improved performance.

Implementation Method 1

The compound achieves conductivities of 1 S/cm with a doping concentration of 10 mol%, enhances thermal stability, and can be processed under various conditions, including vacuum and inert atmospheres, forming stable n-doped layers with improved performance.

Methodology Applied
Scientific EffectElectron transfer: Redox Reactions

Data Source

PatentEP2724388B2Electronic device
Publication Date: 2025.09.24 NOVALED GMBH
  • EP2724388B2 patent drawingFigure 1~2
  • EP2724388B2 patent drawingFigure 3
  • EP2724388B2 patent drawing

AI summary

The present invention relates to an electronic device comprising a compound according to formula 1 A-B (1) and wherein - Ar1 is a C6-C18 arylene, which can be monocyclic or polycyclic and may be optionally substituted by one or more C1-C10-alkyl or C3-C10-cycloalkyl groups, - Ar2 is a C6-C18 arene skeleton, optionally substituted with electron donating groups R4, - B1 and B2 are independently selected from B and Ar2, - B3 is independently selected from the same group as B, - R1, R2, R3 are independently selected from alkyl, arylalkyl, cycloalkyl, aryl, dialkylamino, - x is selected from 0, 1, 2 and 3, wherein for x > 1 each Ar1 may be different, - y is a non-zero integer up to the overall count of valence sites on the arene skeleton, - z is a integer from zero up to the overall count of valence sites on the arene skeleton minus y; as well as a respective compound according to formula A-B.