SAM Connecting Layer for Rough-Surface Perovskite Tandem Cells

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Solution Overview

Problem

The deposition of charge-selective contact layers on rough surfaces in perovskite solar cells is challenging, leading to short circuits and inefficiencies, particularly in tandem and multi-junction solar cells, due to the complexity of conformal deposition on textured substrates.

Innovation Solution

A multilayer system comprising a self-assembled monolayer (SAM) of specific molecules, such as V1193, applied conformally over a substrate layer to serve as a hole-selective contact, enabling efficient charge transport and coverage on rough surfaces, thereby forming a bonding layer between perovskite sub-junction solar cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If organic materials are used as connecting layers in perovskite solar cells, then flexibility and ease of deposition are improved, but stability and moisture resistance deteriorate

Engineering Contradiction:
Improveease of depositionVSAvoidstability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs a composite connecting layer comprising alternating organic and inorganic material layers. The organic layers (e.g., PEDOT:PSS, Alq3) provide ease of deposition and flexibility, while the inorganic layers (e.g., Al2O3, SiO2, TiO2) provide stability and moisture resistance. This composite structure synergistically combines the advantages of both material types, resolving the contradiction between ease of manufacture and reliability.

Inventive Principle:
Principle #40Composite materials

2Productivity

If multiple connecting layers are stacked to improve light absorption, then energy conversion efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveenergy conversion efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the connecting layer into multiple thin sub-layers, each with specific functions. The segmentation includes organic layers for charge transport and inorganic layers for protection and optical management. This segmented approach allows optimization of each layer's thickness and composition to maximize light absorption and energy conversion while maintaining manageable device complexity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connecting layer structure follows a nested pattern where thin inorganic layers are inserted between organic layers, creating an alternating multilayer structure. Each layer is optimized for specific thickness (e.g., organic layers 5-50 nm, inorganic layers 2-20 nm), allowing maximum light absorption and charge extraction efficiency while maintaining a compact overall structure that doesn't excessively increase device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Loss of energy

If thin connecting layers are used to reduce recombination losses, then charge extraction efficiency is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improverecombination lossesVSAvoidmanufacturing precision
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent optimizes the thickness parameters of both organic and inorganic layers to specific ranges (organic: 5-50 nm, inorganic: 2-20 nm) to minimize recombination losses while maintaining manufacturability. By carefully controlling these parameters and using standard deposition techniques, the patent achieves thin enough layers to reduce recombination without requiring extreme manufacturing precision that would be difficult to implement consistently.

Inventive Principle:
Principle #35Parameter changes

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 multilayer system enhances power conversion efficiency, reduces material consumption, and allows scalable production of multi-junction solar cells with minimal parasitic optical absorption and improved stability, overcoming the limitations of conventional methods.

Implementation Method 1

Perovskite solar cells have attracted great interest as a low-cost, high-efficiency alternative to conventional silicon-based solar cells

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

The connecting layer may comprise a first organic layer, a first inorganic layer, a second organic layer, and a second inorganic layer alternately stacked on the first perovskite sub-cell in sequence

Methodology Applied
Scientific EffectCharge carrier conduction: Conduction (electrical)

Data Source

PatentEP3987577B1Perovskite multi-junction solar cell having multi-layer system as connecting layer
Publication Date: 2026.04.29 HELMHOLTZ-ZENTRUM BERLIN FÜR MATERIALIEN UND ENERGIE
  • EP3987577B1 patent drawingFigure 1a~1d
  • EP3987577B1 patent drawingFigure 2
  • EP3987577B1 patent drawingFigure 3

AI summary

The invention relates to a multi-layer system M as a connecting layer for perovskite multi-junction solar cells. The multi-layer system comprises at least two layers, layer A and layer B, wherein layer A is applied in a directly conforming manner to layer B, and wherein layer A is formed as a self-assembled monolayer from at least one molecule type according to formula (I), (I), where m = 1 to 2, L is a connecting fragment, A is an anchor group, and HTF is a hole-transporting fragment, and layer B is formed from at least one of the materials of the group of indium oxide, zinc oxide, tin oxide, nickel oxide, copper oxide, tungsten and molybdenum oxide or mixtures thereof; or silicon oxide or silicon, including amorphous, nano- or multi-crystalline, hydrogen-doped and oxidic layers, in particular a-Si:H, nc-Si:H, a-SiOx:H, nc-SiOx:H, µc-Si:H, µc-SiOx:H. The invention also relates to a method for producing a multi-layer system M according to the invention and to a multi-junction solar cell having a perovskite partial solar cell PZ and a multi-layer system M according to the invention as a connecting layer.