Phosphorus Passivator for Perovskite Defect and Ion Migration Control
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Solution Overview
Problem
Perovskite solar cells suffer from numerous defects in the bulk phase and on the surface, including under-coordinated lead ions, halide vacancies, and ion migration, which affect their optoelectronic performance and stability.
Innovation Solution
A phosphorus-containing passivator with a specific ionic compound structure is introduced, forming strong P—Pb coordination bonds and low-dimensional perovskite interfaces to passivate defects, reducing energy loss and enhancing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If perovskite solar cells are prepared as thin films, then light absorption efficiency is improved, but numerous defects are introduced in the bulk phase and on the surface
Solution Approach 1:
The phosphorus-containing passivator is introduced during the preparation process to preemptively passivate defects before they can form or propagate. The passivator forms strong P—Pb coordination bonds with under-coordinated lead ions and fills halide vacancies during the thin film formation process, preventing defect formation rather than addressing them afterward.
Solution Approach 2:
The phosphorus-containing passivator acts as an intermediary substance between the perovskite precursor materials during film formation. It mediates the crystallization process by coordinating with lead ions and filling vacancies, thereby improving both the quality of the thin film and reducing defect formation during the deposition process.
2Reliability
If conventional passivators are used, then some defects are passivated, but ion migration is not effectively suppressed and stability remains insufficient
Solution Approach 1:
The phosphorus-containing passivator represents a composite functional material that combines multiple passivation mechanisms in one molecule. It simultaneously provides Lewis base coordination through phosphorus lone pairs for defect passivation and forms low-dimensional perovskite structures for ion migration suppression, achieving both functions that conventional single-mode passivators cannot accomplish.
Solution Approach 2:
The passivator exhibits different functional groups with distinct roles: the phosphorus-containing group provides localized coordination bonding for defect passivation, while the organophosphorus salt group forms low-dimensional perovskite phases at interfaces to suppress ion migration. Each part of the molecule performs a specific function tailored to local defect types and interface requirements.
3Reliability
If multiple defect types are present, then comprehensive passivation is needed, but using multiple different passivators increases complexity
Solution Approach 1:
The phosphorus-containing passivator is designed as a universal passivation agent that can address multiple defect types simultaneously. It can passivate under-coordinated lead ions, fill halide vacancies, and suppress ion migration at interfaces all through a single material application, eliminating the need for sequential application of multiple specialized passivators and simplifying the overall processing.
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 phosphorus-containing passivator effectively passivates lead ion and iodide ion vacancies, improving the optoelectronic performance and stability of perovskite solar cells by reducing energy loss and suppressing ion migration.
Implementation Method 1
The lone pair electrons of the organophosphorus group can form strong P—Pb coordination bonds with under-coordinated lead ions in the bulk phase and/or at the upper and lower interfaces of a perovskite light-absorbing layer
Implementation Method 2
the organophosphorus salt group can form low-dimensional perovskite at the upper and lower interfaces of a perovskite layer, passivating the interfaces of the perovskite layer and suppressing ion migration
Implementation Method 3
The halide anions and the halogen-containing anionic groups can respectively passivate iodide ion vacancies, reducing energy loss
Data Source
AI summary
A phosphorus-containing passivator, a perovskite solar cell, a photovoltaic module, a photovoltaic system, and an electric apparatus are provided. The phosphorus-containing passivator includes an ionic compound, the ionic compound includes a cationic group, and the cationic group has a structure represented by formula (I): A-L-B (I); where A represents an organophosphorus group with lone pair electrons, B represents a positively charged organophosphorus salt group, and L represents a linking group between the organophosphorus group and the organophosphorus salt group. The lone pair electrons of the organophosphorus group can form strong P—Pb coordination bonds with under-coordinated lead ions in the bulk phase and/or at the upper and lower interfaces of a perovskite light-absorbing layer, passivating low-coordinated lead ion defects; the organophosphorus salt group can form low-dimensional perovskite at the upper and lower interfaces of a perovskite layer, passivating the interfaces of the perovskite layer and suppressing ion migration.