Perovskite X-ray Sensor Adhesion via PEDOT-Sorbitol Interlayer

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Solution Overview

Problem

The challenge lies in achieving good adhesion between a direct conversion layer comprising perovskites and electrodes in X-ray detectors, particularly for pixelated devices, while maintaining sufficient thickness and resolution, as existing methods face issues with adhesion and industrial-scale fabrication of large-area detectors.

Innovation Solution

Incorporating an electron or hole blocking interlayer with an adhesion promoting additive, such as saccharides or their derivatives, to enhance the adhesion between the perovskite direct conversion layer and electrodes, ensuring high resistivity and minimizing dark current and crosstalk in pixelated detectors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a direct conversion layer comprising perovskites is used in X-ray detectors, then sensitivity and resolution are improved, but adhesion to electrodes deteriorates

Engineering Contradiction:
Improvedetection resolutionVSAvoidadhesion to electrodes
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The patent introduces an interlayer comprising PEDOT and sorbitol as an intermediary between the perovskite direct conversion layer and the electrode. This interlayer acts as a mediator that simultaneously provides adhesion promotion and charge transport functionality, resolving the contradiction between maintaining detection resolution and improving adhesion strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a composite material system consisting of PEDOT (conducting polymer) and sorbitol (adhesion promoter) in the interlayer. This composite structure combines the charge transport properties of PEDOT with the adhesion enhancement provided by sorbitol, thereby achieving both good electrical performance and strong adhesion to the perovskite layer.

Inventive Principle:
Principle #40Composite materials

2Reliability

If thick perovskite layers (>100 μm) are used to improve sensitivity, then detection sensitivity is improved, but adhesion and fabrication difficulty worsen

Engineering Contradiction:
Improvedetection sensitivityVSAvoidfabrication difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The interlayer comprising PEDOT and sorbitol serves as a mediator that enables the fabrication of thick perovskite layers (>100 μm) by providing robust adhesion during the deposition process. This intermediary layer prevents delamination and cracking that would otherwise occur with thick perovskite layers, thereby enabling high sensitivity detection while maintaining ease of manufacture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes parameter changes in the interlayer composition (PEDOT:sorbitol ratio, thickness) to optimize the balance between adhesion and charge transport. By adjusting these parameters, the system can accommodate thick perovskite layers while maintaining good adhesion and electrical performance, thus improving sensitivity without significantly increasing fabrication difficulty.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If conventional electrode materials are used with perovskite layers, then charge transport is efficient, but adhesion is insufficient

Engineering Contradiction:
Improvecharge transport efficiencyVSAvoidadhesion
Core Design Contradiction:
Use of energy by moving objectVSStrength

Solution Approach 1:

The patent employs a composite material system in the interlayer combining PEDOT (for charge transport) and sorbitol (for adhesion). This composite structure allows the electrode interface to maintain efficient charge transport properties while simultaneously achieving strong adhesion to the perovskite direct conversion layer, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The interlayer acts as an intermediary that bridges the electrode and perovskite layer, providing both adhesion and charge transport pathways. This intermediary structure allows conventional electrode materials to maintain their charge transport efficiency while the interlayer compensates for insufficient adhesion through the sorbitol component.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables the production of X-ray detectors with improved adhesion and sensitivity, facilitating the fabrication of large-area, high-resolution pixelated detectors by maintaining sufficient resistivity and reducing defects, thus enabling industrial-scale production.

Implementation Method 1

an electron or hole blocking interlayer with an adhesion promoting additive, such as saccharides or their derivatives, to enhance the adhesion between the perovskite direct conversion layer and electrodes

Methodology Applied
Scientific EffectAdhesion promotion: Adhesive

Implementation Method 2

For direct conversion, X-ray quanta excite a particle, which results in a formation of electron/hole pairs

Methodology Applied
Scientific EffectDirect conversion: Photoelectric Effect

Implementation Method 3

an electron blocking interlayer comprising an adhesion promoting additive

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Implementation Method 4

a hole blocking interlayer comprising an adhesion promoting additive

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP3474339B1X-ray image sensor with adhesion promotive interlayer and soft-sintered perovskite active layer
Publication Date: 2024.11.06 SIEMENS HEALTHINEERS AG
  • EP3474339B1 patent drawingFigure 1
  • EP3474339B1 patent drawingFigure 2
  • EP3474339B1 patent drawingFigure 3~4

AI summary

The present invention relates to an X-ray detector, particularly a pixelated flat panel X-Ray detector using semiconducting perovskites as direct converting layer, comprising a top electrode (1), a photoactive layer (3) comprising at least one perovskite, and a bottom electrode (5'), wherein the X-ray detector additionally comprises an electron blocking interlayer (2) and/or a hole blocking interlayer (4') comprising an adhesion promoting additive, as well as a method of manufacturing such an X-ray detector.