Perovskite Solar Cell Hole-Transporting Layer Stability

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Solution Overview

Problem

Conventional photoelectric conversion elements, particularly perovskite solar cells, experience a decline in photoelectric conversion efficiency when exposed to high illuminance for extended periods, leading to durability issues under high temperature and high humidity conditions.

Innovation Solution

Incorporation of a compound represented by General Formula (1) or (1a) in the hole-transporting layer, which includes an alkali metal and specific functional groups, enhances the photoelectric conversion efficiency by maintaining high performance even after prolonged exposure to high illuminance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional hole-transporting materials (Spiro and Li-TFSI) are used in perovskite solar cells, then the device can be produced by conventional printing units with reduced cost, but the durability under high temperature and high humidity conditions deteriorates

Engineering Contradiction:
Improveproduction costVSAvoiddurability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the chemical structure of the hole-transporting material by introducing a boron atom bonded to three nitrogen atoms (forming a boron-nitrogen heterocyclic structure) and incorporating electron-attracting groups. This structural parameter change maintains compatibility with conventional printing production while fundamentally improving stability under high temperature and humidity conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite hole-transporting material that combines the boron-nitrogen heterocyclic core structure with electron-attracting groups (such as carbonyl, sulphonyl, or sulfinyl groups). This composite structure integrates the advantages of both conventional materials (ease of manufacture) and stable materials (durability), achieving both low production cost and high reliability.

Inventive Principle:
Principle #40Composite materials

2Productivity

If perovskite solar cells are exposed to light of high illuminance for a long period of time, then energy harvesting is achieved, but photoelectric conversion efficiency deteriorates

Engineering Contradiction:
Improveenergy harvestingVSAvoidphotoelectric conversion efficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent incorporates the stable boron-nitrogen heterocyclic hole-transporting material into the device structure before exposure to high illuminance conditions. This preliminary structural preparation ensures that the photoelectric conversion efficiency is maintained during prolonged high-illuminance operation, preventing the deterioration that occurs with conventional materials.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If organic semiconductor components and halogen-containing polymers are used to improve high temperature and humidity durability, then stability is enhanced, but the structural complexity increases

Engineering Contradiction:
ImprovestabilityVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and utilizes the essential stability-providing features (electron-attracting groups and heteroatom structures) from complex halogen-containing polymers and applies them to a simpler boron-nitrogen heterocyclic framework. This extraction approach maintains the stability benefits while reducing the overall structural complexity compared to using full halogen-containing polymer structures.

Inventive Principle:
Principle #2Taking out (Extraction)

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 proposed solution effectively maintains high photoelectric conversion efficiency and durability by using a compound with specific functional groups in the hole-transporting layer, ensuring stable performance under challenging environmental conditions.

Implementation Method 1

a hole-transporting layer; and a second electrode

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

photoelectric conversion element includes: a first electrode; a perovskite layer

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP3839994B1Photoelectric conversion element, photoelectric conversion module, electronic device, and power supply module
Publication Date: 2023.07.05 RICOH CO LTD
  • EP3839994B1 patent drawingFigure 1~2
  • EP3839994B1 patent drawingFigure 3~4
  • EP3839994B1 patent drawingFigure 5~6

AI summary

Photoelectric conversion element including: first electrode (2, 2a, 2b); perovskite layer (5); hole-transporting layer (6); and second electrode (7), wherein the hole-transporting layer (6) includes compound represented by General Formula (1) or (la) below: where M represents alkali metal; X1 and X2, which may be identical to or different from each other, each represent at least one selected from the group consisting of carbonyl group, sulphonyl group, and sulfinyl group; and X3 represents at least one selected from the group consisting of bivalent alkyl group, alkenyl group, and aryl group, and hydrogen atom of the bivalent alkyl group, the alkenyl group, and the aryl group may be substituted with halogen atom; where M+ represents organic cation; and X1, X2, and X3 have the same meanings as X1, X2, and X3 in the General Formula (1).