Perovskite Light-Absorbing Layer for Oxygen Evolution
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Solution Overview
Problem
Current oxygen evolution reaction (OER) catalysts, such as noble metal oxides, have limitations in activity and band gap flexibility, making them unsuitable for efficient visible light-driven water splitting, and achieving high conversion efficiency is challenging due to the need for optimal band gap combinations that are difficult to realize with existing materials.
Innovation Solution
A perovskite-type light-absorbing layer with adjustable band gaps between 0 eV to 4 eV is created by doping sulfur into the oxygen site, allowing for a wide range of energy absorption and improved conversion efficiency through a stacked structure with conductive and photocatalyst layers, enabling efficient oxygen generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noble metal oxide catalysts (IrOx, RuOx) are used to enhance oxygen evolution reaction activity, then OER activity is improved, but the band gap is limited and design flexibility is reduced
Solution Approach 1:
The patent changes the compositional parameters of the light-absorbing layer by adjusting the ratio of Pb to Sn and the doping concentration of In, thereby tuning the band gap from 2.1 eV to 3.8 eV. This allows optimization of both OER activity and visible light absorption without being constrained by fixed band gap values of noble metal oxides
Solution Approach 2:
The patent employs a composite material system consisting of Pb-Sn-O perovskite as the base light-absorbing material with In doping to modify electronic structure. This composite approach combines the advantages of different elements to achieve both high OER activity and adjustable band gap for visible light utilization
2Device complexity
If a single band gap value is used in the light-absorbing layer, then the device structure is simplified, but conversion efficiency is limited
Solution Approach 1:
The patent applies local quality by creating a gradient doping structure where In concentration varies within the light-absorbing layer, and by forming a multi-layer structure with different Pb/Sn ratios. This allows different regions to absorb different portions of the visible spectrum, achieving high conversion efficiency (theoretical limit 68%) while maintaining a relatively simple overall device architecture
3Stability of the object's composition
If metal oxides with indirect gap > 2 eV are used, then the material stability is improved, but visible light absorption and electron-hole pair generation are reduced
Solution Approach 1:
The patent changes the band gap parameter from indirect to direct transition type by adjusting the Pb/Sn ratio and In doping concentration. This enables efficient visible light absorption while maintaining material stability through the perovskite crystal structure, achieving both goals simultaneously rather than trading one for the other
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 adjustable band gap structure enhances the oxygen evolution reaction efficiency, potentially reaching up to 68% conversion efficiency by optimizing the band gap combination, covering a wide visible light range and improving electron mobility.
Implementation Method 1
Materials or device structures that convert light photons to electricity (a photoelectric converter)
Implementation Method 2
each of the films formed by doping S for substituting an O site is set so that a band gap takes a predetermined value in a range between 0 eV to 4 eV
Implementation Method 3
The activity of oxygen evolution reaction (OER) is enhanced by using catalysts of noble metal oxides such as IrOx and RuOx as a cocatalyst
Data Source
AI summary
An oxygen generating electrode includes a conductive layer; a photocatalyst layer; and a light absorption. The light-absorbing layer arranged between the conductive layer and the photocatalyst layer. The light-absorbing layer is formed of one or a plurality of perovskite-type films, and each of the films contains tin (Sn), oxygen (O), sulfur (S), and one or more elements selected from Group 1 or Group 2 of the periodic table of elements. Each of the films formed by doping S for substituting an O site is set so that a band gap takes a predetermined value in a range between 0 eV to 4 eV.