Hydrazine Reductant for Perovskite Precursor Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Perovskite solar cells face poor reproducibility and performance due to the degradation of precursor solutions, particularly the oxidation of I− ions to I2, which affects the stability and efficiency of photovoltaic devices.

Innovation Solution

A low-cost hydrazine reductant is used to reduce I2 back to I− in aged precursor solutions, stabilizing the perovskite films and enhancing their performance by reducing oxidation and interfacial voids, thereby improving the reproducibility and efficiency of perovskite solar cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If perovskite precursor solutions are stored for extended periods, then manufacturing cost and time efficiency are improved, but the solutions degrade due to oxidation of I− to I2, causing poor reproducibility and performance

Engineering Contradiction:

Improveprecursor solution storage timeVSAvoiddevice reproducibility

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by adding a reducing agent to the precursor solution before storage to prevent oxidation. The reducing agent reacts with I2 as it forms, preventing the oxidation degradation that would otherwise occur during storage, thus maintaining solution stability over extended periods while ensuring device reproducibility

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the harmful oxidation effect into a beneficial process by using the reducing agent to transform I2 (harmful oxidation product) back into I− (useful precursor). This chemical conversion maintains the integrity of the perovskite precursor solution during storage, enabling both extended storage time and high device reproducibility

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Power

If fresh precursor solutions are used, then power conversion efficiency is maintained, but manufacturing cost increases and productivity decreases due to frequent preparation

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidmanufacturing efficiency

Core Design Contradiction:

PowerVSProductivity

Solution Approach 1:

The patent applies preliminary action by preparing the precursor solution with a reducing agent added in advance, which prevents degradation during storage. This allows the solution to be prepared once and used repeatedly over extended periods, maintaining power conversion efficiency equivalent to fresh solutions while significantly improving manufacturing productivity by eliminating frequent preparation cycles

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If perovskite precursor solutions are aged, then storage flexibility is improved, but oxidation occurs leading to interfacial voids and reduced device performance

Engineering Contradiction:

Improvestorage flexibilityVSAvoidoxidation and interfacial voids

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by incorporating a reducing agent into the precursor solution before storage, which proactively prevents oxidation during the aging process. This chemical protection mechanism maintains solution stability over extended storage periods, providing storage flexibility while preventing the formation of interfacial voids and maintaining device performance

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The reducing agent acts as an intermediary substance that mediates between the perovskite precursor and oxygen. It preferentially reacts with oxygen or I2 formed during storage, protecting the main perovskite precursor from oxidation and preventing interfacial void formation, thus enabling both storage flexibility and high device performance

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

The use of the hydrazine reductant effectively restores the stability of perovskite precursor solutions, leading to high power conversion efficiencies and exceptional operational stability in perovskite solar cells by reducing oxidation and interfacial voids, thus addressing the issue of batch-to-batch variation and degradation.

Implementation Method 1

A low-cost hydrazine reductant is used to reduce I2 back to I− in aged precursor solutions, stabilizing the perovskite films and enhancing their performance by reducing oxidation

Methodology Applied

Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentUS20240158658A1Iodine reduction for reproducible and high performance perovskite solar cells and modules

Publication Date: 2024.05.16 THE UNIV OF NORTH CAROLINA AT CHAPEL HILL

AI summary

Described herein are oxidative-resistant ink solutions, comprising: a first composition of formula ABI3-yXy; one or more solvents; and a compound of Formula (II), or a salt thereof, wherein A, B, y, and X are described herein. Methods for preparing perovskite films using the oxidative-resistant ink solutions and the use of the films in solar cells and solar modules are additionally described. In certain embodiments, further described are methods of preparing perovskite films having reduced interfacial voids, comprising adding a compound of Formula (II), or a salt thereof, to the perovskite precursor solution used to prepare the film.