Perovskite Solar Cell Interface Passivation for Stability
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Solution Overview
Problem
Low-temperature-processed metal halide perovskite solar cells (PSCs) suffer from inferior long-term device operational stability and solar-to-electric power conversion efficiency (PCE) compared to high-temperature-processed counterparts, and have not demonstrated high efficiency and large area compatibility necessary for industrialization.
Innovation Solution
The use of a ligand, such as chlorine, to passivate the interface between the electron transport layer and the perovskite layer in perovskite-based optoelectronic devices, reducing electron-hole recombination and enhancing the stability and efficiency of low-temperature-processed planar PSCs by forming a stable interface with the electron transport layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature-sintered mesoporous TiO2 is used as electron transport layer, then power conversion efficiency and device stability are improved, but manufacturing complexity increases and flexible module development is hampered
Solution Approach 1:
The patent changes the processing temperature parameter from high-temperature (450-550°C) sintering to low-temperature (≤150°C) solution processing. This is achieved by using colloidal nanoparticles and solution-based deposition methods instead of high-temperature sintering, thereby maintaining device performance while simplifying manufacturing and enabling flexible substrate compatibility.
Solution Approach 2:
The patent replaces the thermal field-based high-temperature sintering process with a solution-based chemical deposition process. Instead of using high thermal energy to form the electron transport layer, the invention uses solution processing at low temperatures, substituting a thermal-mechanical system with a chemical-solution system that achieves similar functional results with reduced complexity.
2Device complexity
If low-temperature solution-processed electron transport layer is used, then manufacturing complexity is reduced and flexible modules become feasible, but long-term device operational stability and power conversion efficiency deteriorate
Solution Approach 1:
The patent introduces an interface passivation layer as an intermediary between the low-temperature solution-processed electron transport layer and the perovskite layer. This intermediate layer passivates interfacial defects and reduces non-radiative recombination, thereby improving device stability and efficiency without requiring high-temperature processing of the electron transport layer itself.
Solution Approach 2:
The patent creates a composite structure by combining the low-temperature solution-processed electron transport layer with an interface passivation layer. This composite approach allows the electron transport layer to maintain its manufacturing advantages while the passivation layer compensates for interfacial defects, achieving both simplicity and stability.
3Ease of manufacture
If low-temperature planar perovskite solar cells are fabricated, then manufacturing cost and complexity are reduced, but power conversion efficiency and large area compatibility remain insufficient for industrialization
Solution Approach 1:
The patent applies preliminary interface passivation treatment to the electron transport layer before depositing the perovskite layer. By pre-passivating the interface with ligands or passivation layers, the interfacial quality is improved in advance, ensuring high power conversion efficiency is achieved during low-temperature planar fabrication without requiring complex post-processing or high-temperature steps.
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 results in hysteresis-free perovskite solar cells with certified PCEs over 20%, excellent operational stability, and compatibility with flexible substrates, enabling scalable and efficient production of perovskite-based tandem devices.
Implementation Method 1
the electron transport layer having a surface located at an interface or junction between the electron transport layer and the light-absorbing perovskite layer at least partially capped with a ligand Z, wherein said ligand Z is selected to passivate surface states at said interface or junction
Data Source
AI summary
Disclosed herein are perovskite based optoelectronic devices made entirely via solution-processing at low temperatures (<150° C.) which provide for simple manufacturing, compatibility with flexible substrates, and perovskite-based tandem devices. These perovskite based optoelectronic devices are produced using an electron transport layer on which the perovskite layer is formed which is passivated using a ligand selected to reduce electron-hole recombination at the interface between the electron transport layer and the perovskite layer.