Porous Conductive Powder Layer for Dye-Sensitized Solar Cells

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Solution Overview

Problem

Dye-sensitized solar cells (DSCs) face limitations due to the low conductivity of transparent conducting oxides (TCO), which restricts the width of solar cell segments and increases costs, and existing methods like vacuum deposition have drawbacks such as slow processing, high equipment costs, and ion and dye diffusion issues.

Innovation Solution

A porous conductive powder layer (PCPL) is formed by depositing electrically conductive metal powders, such as titanium or its alloys, onto a substrate using printing techniques, which enhances electrical conductivity and mechanical stability, allowing for wider solar cell segments and reduced material waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If vacuum deposition is used to deposit porous metal layer, then electrical conductivity is improved, but processing speed is slow and equipment cost is high

Engineering Contradiction:
Improveelectrical conductivityVSAvoidprocessing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the vacuum deposition process (physical field method) with a printing process (mechanical method) for depositing conductive powder. This substitution eliminates the need for expensive vacuum equipment and significantly increases processing speed while maintaining electrical conductivity through the use of conductive powders that form continuous networks upon printing and sintering.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If TCO-based glass is used for back contact, then electrical conductivity is improved, but material cost increases

Engineering Contradiction:
Improveelectrical conductivityVSAvoidmaterial cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive TCO-based glass with a cost-effective alternative: a printed and sintered conductive powder layer on a simple glass substrate. The conductive powder layer (made from inexpensive metals like silver, aluminum, or their oxides) provides the necessary electrical conductivity at a fraction of the cost of TCO glass, while the simple glass substrate serves as the mechanical support.

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

3Device complexity

If segment width is increased to reduce manufacturing complexity, then device complexity is reduced, but electronic ohmic losses in TCO layer increase

Engineering Contradiction:
Improvemanufacturing complexityVSAvoidelectronic ohmic losses
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent changes the electrical conductivity parameter of the back contact by replacing TCO with a printed conductive powder layer that has superior conductivity. This parameter change allows for increased segment width without incurring ohmic losses, as the conductive powder layer maintains low resistance even over larger areas, thus enabling wider segments without energy loss.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If printing technique is used to deposit conductive powder, then processing speed is improved and cost is reduced, but initial electrical conductivity is lower

Engineering Contradiction:
Improveprocessing speedVSAvoidinitial electrical conductivity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies a preliminary sintering step after printing the conductive powder layer. This sintering process (heating to remove organic binders and fuse the powder particles) transforms the initially low-conductivity printed powder into a high-conductivity continuous metal network. The preliminary printing deposits the conductive material in a form that can be easily processed, and the subsequent sintering activates its electrical conductivity.

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 PCPL increases current-handling capability, reduces the need for TCO, and provides a cost-effective manufacturing method with faster processing times and improved ion and dye transport, leading to enhanced light-to-electric energy conversion efficiency.

Implementation Method 1

A porous conductive powder layer (PCPL) is formed by depositing electrically conductive metal powders, such as titanium or its alloys, onto a substrate using printing techniques

Methodology Applied
Scientific EffectPrinting deposition: Deposition (physical)

Implementation Method 2

improved ion and dye transport

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2625703B1Method for manufacture of an improved dye- sensitized solar cell
Publication Date: 2018.02.21 NLAB SOLAR AB
  • EP2625703B1 patent drawingFigure 1~2
  • EP2625703B1 patent drawingFigure 3~4
  • EP2625703B1 patent drawingFigure 5~6

AI summary

A method for producing a Dye- Sensitized Solar cell (DSC) comprising a substrate, a working electrode, a back contact for extracting photo-generated electrons, an electrolyte, and a counter electrode where the back contact and/ or the counter electrode is formed by a porous conductive powder layer, PCPL. The PCPL is prepared by the following steps: a. powder preparation; b. powder ink preparation; c. powder ink deposition; d. powder layer heating; e. powder layer compaction; and f. powder layer after treatment.