Photochemical Electrode Crystal Orientation for Hydrogen Generation
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Solution Overview
Problem
In artificial photosynthesis systems, the recombination of electrons and holes in photocatalytic semiconductor materials reduces the amount of charge available for hydrogen generation, limiting the photocurrent and efficiency of clean energy production.
Innovation Solution
A photochemical electrode is designed with an electrically-conductive layer and a photo-excited material layer, where the lattice plane with the highest atomic density in the crystal structure of the photo-excited material is oriented in the surface direction, enhancing charge separation and photocurrent generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photocatalytic semiconductor materials are used in artificial photosynthesis systems, then hydrogen generation is enabled, but electron-hole recombination reduces the amount of charge available for hydrogen generation, limiting photocurrent and efficiency
Solution Approach 1:
The patent applies local quality by creating a non-uniform electric field through the wedge-shaped semiconductor crystal structure. The electric field strength varies spatially, being stronger at the thin end and weaker at the thick end, which optimizes charge separation locally throughout the material volume and reduces electron-hole recombination losses
Solution Approach 2:
The patent employs asymmetry by using a wedge-shaped semiconductor crystal with non-parallel side surfaces. This asymmetric geometry creates an internal electric field that drives charge separation, with the field direction and magnitude varying across the crystal structure, thereby improving photocurrent generation and reducing recombination
2Productivity
If the photo-excited material layer is formed with random crystal orientation, then manufacturing is simpler, but the photocurrent generation efficiency is reduced due to suboptimal charge separation
Solution Approach 1:
The patent applies parameter changes by controlling the crystal growth parameters to achieve a specific wedge shape with defined angles. By adjusting the growth conditions to produce this specific geometric parameter configuration, the internal electric field is optimized for charge separation, thereby improving photocurrent efficiency while maintaining manufacturability through controlled crystal growth processes
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 configuration increases the photocurrent for hydrogen generation, improving the efficiency of clean energy production by minimizing electron-hole recombination and optimizing charge utilization.
Implementation Method 1
a photochemical electrode includes: an electrically-conductive layer; and a photo-excited material layer including a photo-excited material provided over the electrically-conductive layer
Data Source
AI summary
A photochemical electrode includes: an electrically-conductive layer; and a photo-excited material layer including a photo-excited material provided over the electrically-conductive layer, wherein in a surface of the photo-excited material layer, a lattice plane having highest atomic density in a crystal structure of the photo-excited material is oriented in a surface direction of the surface of the photo-excited material layer.