Perovskite Solar Cell Crystalline Halide Layer Stability

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Solution Overview

Problem

Perovskite solar cells face challenges with high hysteresis and rapid deterioration, limiting their commercialization due to instability and short lifespan, especially when exposed to moisture.

Innovation Solution

A perovskite solar cell design incorporating a crystalline halide layer with a wide band-gap energy, formed by reacting an organometal halide with a quaternary ammonium salt, which provides an energy barrier to suppress recombination and enhance stability, and is fabricated using a simple solution coating method.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a perovskite solar cell uses organometal halide as light absorber to achieve high efficiency, then photoelectric conversion efficiency is improved, but stability and lifespan deteriorate due to rapid deterioration and large hysteresis

Engineering Contradiction:

Improvephotoelectric conversion efficiencyVSAvoidstability and lifespan

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent uses a composite structure consisting of an organometal halide perovskite layer combined with a wide band-gap crystalline material layer. The perovskite layer (e.g., MAPbI3) provides high photoelectric conversion efficiency, while the wide band-gap layer (e.g., (NH4)2PbBr6 or quaternary ammonium salt-modified perovskite) provides stability and moisture resistance. This composite approach allows the solar cell to maintain high efficiency while significantly improving stability and lifespan.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If a perovskite solar cell uses conventional materials without wide band-gap layer, then manufacturing is simple, but deterioration due to moisture occurs rapidly

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidmoisture-induced deterioration

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The wide band-gap crystalline material layer acts as an intermediary protective layer between the organometal halide perovskite and the external environment (moisture). This intermediate layer has high moisture resistance and prevents water molecules from attacking the perovskite layer, thereby significantly reducing moisture-induced deterioration while maintaining manufacturing simplicity through solution-based deposition methods.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If a perovskite solar cell lacks wide band-gap material with appropriate energy levels, then device structure is simple, but recombination of charges occurs and efficiency is lost

Engineering Contradiction:

Improvestructure complexityVSAvoidcharge recombination loss

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent changes the band gap energy parameter of the crystalline material layer to be wider than the perovskite layer (e.g., Eg > 3.0 eV for the wide band-gap layer vs. Eg ≈ 1.5 eV for MAPbI3). This parameter change creates an energy level offset that forms an energy barrier, preventing charge recombination at the interface while maintaining a relatively simple device structure. The wide band-gap layer's valence band maximum is lower than that of the perovskite, creating an effective barrier against hole back-transfer and recombination.

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 solution significantly improves the photoelectric conversion efficiency, stability, and lifespan of the solar cell by reducing recombination and enhancing moisture resistance, maintaining efficiency even at high humidity and temperature.

Implementation Method 1

the crystalline halide has a band gap energy higher than a band gap energy of an organometal halide of the organometal halide layer, and has a valence band maximum energy level lower than a valence band maximum energy level of the organometal halide

Methodology Applied

Scientific EffectBand gap energy barrier:

Implementation Method 2

An organometal halide having a perovskite structure... using the organic/inorganic organometal halide as a light absorber

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3416206B1Perovskite solar cell with wide band-gap and fabrication method thereof

Publication Date: 2022.10.05 KOREA RES INST OF CHEM TECH

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Figure 3(a)~3(b)

AI summary

Provided is a perovskite solar cell, and more particularly, a perovskite solar cell including an organometal halide layer having a perovskite structure; and a crystalline material layer stacked while forming an interface with the organometal halide layer, wherein a crystalline material of the crystalline material layer is a crystalline halide having a crystal structure different from the perovskite structure, and the crystalline halide has a band gap energy higher than a band gap energy of an organometal halide of the organometal halide layer, and has a valence band maximum energy level lower than a valence band maximum energy level of the organometal halide.