Wurtzite GaZnNO Solid Solution for Narrow Bandgap Solar Absorption
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Solution Overview
Problem
Existing photoexcitation materials, such as gallium nitride (GaN) and zinc oxide (ZnO), have wide forbidden bandwidths, limiting their ability to utilize solar energy efficiently, as they are primarily responsive to ultraviolet light, and their solid solutions also face limitations in narrowing the bandwidth for broader solar spectrum absorption.
Innovation Solution
A wurtzite type solid solution crystal containing gallium, zinc, nitrogen, and oxygen, where the existence ratio of nitrogen or oxygen as a first adjacent atom and gallium or zinc as a second adjacent atom satisfies a specific relational expression, is developed, with a formula GaxNxZn1-x, where x ranges from 0.00 to 1.00, particularly 0.25≤x≤0.75, to achieve a narrower forbidden bandwidth, enhancing light energy utilization by adjusting the interatomic distances and crystal structure through nano particle deposition (NPD) to form thin films with reduced bandgap energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If existing photoexcitation materials like GaN and ZnO are used, then they have good structural stability and material reliability, but their wide forbidden bandwidths limit their ability to utilize solar energy efficiently
Solution Approach 1:
The patent creates a solid solution material GaxNxZn1-xO1-x that combines gallium nitride and zinc oxide in a wurtzite crystal structure. This composite approach allows the material to inherit the structural stability of both parent compounds while achieving a reduced forbidden bandwidth through compositional control, enabling efficient solar energy utilization across a broader spectrum.
Solution Approach 2:
The patent systematically varies the compositional parameter x in the formula GaxNxZn1-xO1-x to control the forbidden bandwidth. By adjusting the ratio of gallium to zinc and nitrogen to oxygen while maintaining the wurtzite structure, the material achieves optimal solar energy absorption with a forbidden bandwidth of 2.5 eV or less, particularly 2.2 eV at x=0.5.
2Use of energy by moving object
If the forbidden bandwidth is narrowed to absorb broader solar spectrum, then solar energy utilization improves, but the crystal structure stability may be compromised
Solution Approach 1:
The patent utilizes compositional parameter x as a control variable to tune the forbidden bandwidth while preserving the wurtzite crystal structure. The solid solution formulation GaxNxZn1-xO1-x allows continuous adjustment of electronic properties without disrupting the underlying crystal lattice stability, achieving bandgap reduction to 2.5 eV or less while maintaining structural integrity.
Solution Approach 2:
By forming a solid solution that combines GaN and ZnO in specific ratios within the wurtzite structure, the patent achieves a composite material that simultaneously provides broad solar spectrum absorption and structural stability. The synergistic combination of different atomic compositions within the same crystal framework enables both improved light energy utilization and maintained compositional stability.
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 solution achieves a narrower forbidden bandwidth, improving the utilization efficiency of sunlight by allowing absorption of a broader solar spectrum, with the bandgap energy reduced to 2.5 eV or less, specifically 2.2 eV at x=0.5, and further narrowing the bandwidth through reduced inter-metal ion distances, leading to higher light energy use efficiency.
Implementation Method 1
a photoexcitation material includes: a wurtzite type solid solution crystal containing gallium, zinc, nitrogen and oxygen... achieving a narrower forbidden bandwidth, improving the utilization efficiency of sunlight by allowing absorption of a broader solar spectrum
Implementation Method 2
a peak (A) of an existence ratio of nitrogen or oxygen which is a first adjacent atom of the gallium or zinc and a peak (B) of an existence ratio of gallium or zinc which is a second adjacent atom of the gallium or zinc satisfy a relational expression of A>B in a relationship between a distance and the existence ratio of the adjacent atom of the gallium or zinc, the relationship being obtained from an extended X-ray absorption fine structure analysis
Data Source
AI summary
A photoexcitation material includes: a wurtzite type solid solution crystal containing t gallium, zinc, nitrogen and oxygen, wherein a peak (A) of an existence ratio of nitrogen or oxygen which is a first adjacent atom of the gallium or zinc and a peak (B) of an existence ratio of gallium or zinc which is a second adjacent atom of the gallium or zinc satisfy a relational expression of A>B in a relationship between a distance and the existence ratio of the adjacent atom of the gallium or zinc, the relationship being obtained from an extended X-ray absorption fine structure analysis.