Hole-Transport Layer Solvent Control for Durable Photoelectric Conversion

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Solution Overview

Problem

Existing photoelectric conversion elements, such as dye-sensitized and perovskite solar cells, face issues with solvent evaporation and leakage, leading to reduced durability and output retention, especially in low illuminance and varying temperature environments.

Innovation Solution

Incorporating a hole-transporting layer with lithium salt having an asymmetric structure and controlling the solvent amount to 5.4 to 30 µg/mm³, along with a photoelectric conversion layer design that includes a first and second electrode, enhances durability and output retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a dye-sensitized solar battery cell encapsulates an electrolytic solution, then charge generation capability is improved, but evaporation or leakage of the solution occurs leading to reduced durability

Engineering Contradiction:
Improvecharge generation capabilityVSAvoiddurability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent changes the physical state of the electrolyte from liquid to solid by using a solid p-type semiconductor material, thereby eliminating evaporation and leakage issues while maintaining charge generation capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a solid p-type semiconductor material that simplifies the structure by eliminating the need for encapsulation, making the device more durable and easier to manufacture

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

2Ease of manufacture

If the solvent amount in the hole-transporting layer is not controlled, then manufacturing is easier, but phase separation occurs leading to reduced output retention

Engineering Contradiction:
Improvemanufacturing easeVSAvoidoutput retention
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent specifies a precise solvent amount range (5.4 to 30 µg/mm³) to prevent phase separation and ensure stable output retention, balancing manufacturing ease with performance reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a solid p-type semiconductor material that acts as a solid electrolyte, eliminating liquid solvent issues while maintaining ease of manufacture through simplified processing

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Power

If conventional photoelectric conversion elements are used in low illuminance environments, then power generation is achieved, but output is insufficient due to solvent evaporation and leakage

Engineering Contradiction:
Improvepower generationVSAvoidoutput retention
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent uses a solid p-type semiconductor material that prevents solvent evaporation and leakage, thereby improving output retention in low illuminance environments while maintaining power generation capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure with a solid p-type semiconductor material combined with a hole-transporting layer, achieving both high power generation and excellent output retention in varying environmental conditions

Inventive Principle:
Principle #40Composite materials

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 solution significantly improves durability and maintains high output in low illuminance conditions across varying temperatures by reducing solvent-induced phase separation and enhancing charge transfer efficiency.

Implementation Method 1

enhancing charge transfer efficiency

Methodology Applied
Scientific EffectCharge transfer: Conduction (electrical)

Implementation Method 2

solar battery cells that can efficiently generate electric power

Methodology Applied
Scientific EffectPhotoelectric conversion: Photovoltaic Effect

Data Source

PatentEP4092704B1Photoelectric conversion element and method for producing photoelectric conversion element, photoelectric conversion module, and electronic device
Publication Date: 2025.07.09 RICOH CO LTD
  • EP4092704B1 patent drawingFigure 1~2
  • EP4092704B1 patent drawingFigure 3~4
  • EP4092704B1 patent drawingFigure 5~6

AI summary

Provided is a photoelectric conversion element including a first electrode, a photoelectric conversion layer, and a second electrode. The photoelectric conversion layer includes a hole-transporting layer, the hole-transporting layer includes lithium salt having an asymmetric structure, and an amount of a solvent per unit volume of the hole-transporting layer is 30 µg/mm3 or less.