SrZn2N2 Multi-Junction Light Energy Conversion Element
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Solution Overview
Problem
Current multi-junction light energy conversion devices face inefficiencies due to unsuitable band gaps in stacked semiconductor materials, particularly in tandem structures for solar cells and solar water splitting, where optimal band gaps for efficient energy conversion are not consistently achieved.
Innovation Solution
A multi-junction light energy conversion element is designed with a first light energy conversion layer containing SrZn2N2, which has a suitable band gap of not less than 1.5 eV and not more than 2.2 eV, and a second layer with a narrower band gap of not less than 0.8 eV and not more than 1.5 eV, optimized through crystal structure calculations and fabrication methods involving sintering under nitrogen atmospheres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional semiconductor materials are used in multi-junction structures, then device complexity is reduced, but energy conversion efficiency deteriorates due to unsuitable band gaps
Solution Approach 1:
The patent changes the band gap parameter of the semiconductor material by introducing SrZn2N2 with a specifically controlled band gap of 1.6-1.8 eV. This parameter optimization enables the material to efficiently absorb sunlight in the 400-750 nm range, directly improving energy conversion efficiency in the upstream layer of multi-junction structures
Solution Approach 2:
The patent employs composite material design by stacking SrZn2N2 with other semiconductor materials having different band gaps to form multi-junction structures. This composite approach allows each layer to capture different portions of the solar spectrum, achieving synergistic improvement in overall energy conversion efficiency while maintaining manageable device complexity
2Productivity
If tandem structures with two semiconductors are designed, then light absorption coverage is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by optimizing the band gap of SrZn2N2 specifically for the upstream layer position in the tandem structure. The material's band gap of 1.6-1.8 eV is tailored to absorb high-energy photons in the 400-750 nm range, while the downstream layer uses materials optimized for lower energy photons. This localized optimization simplifies the overall manufacturing process by clearly defining functional requirements for each layer
3Productivity
If SrZn2N2 is used as upstream material, then energy conversion efficiency is improved, but fabrication process complexity increases
Solution Approach 1:
The patent controls the band gap parameter of SrZn2N2 within the optimal range of 1.6-1.8 eV through composition control and processing conditions. This parameter optimization achieves high energy conversion efficiency while maintaining compatibility with conventional fabrication processes, avoiding excessive complexity in the fabrication process
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 enhances light absorption and carrier transportation, leading to improved energy conversion efficiency and the ability to efficiently split water using sunlight, with SrZn2N2 serving as an effective upstream material in the multi-junction structure.
Implementation Method 1
A semiconductor is irradiated with light having energy of not less than a band gap of the semiconductor to generate a pair of an electron and a hole in the semiconductor
Implementation Method 2
the first light energy conversion layer containing SrZn2N2; and a second light energy conversion layer containing an light energy conversion material, wherein the light energy conversion material has a narrower band gap than the SrZn2N2
Data Source
AI summary
The present disclosure is to provide a multi-junction light energy conversion element including a material having a band gap suitable for a light energy conversion layer located upstream in an incidence direction of light. The present disclosure provides a light energy conversion element, comprising a first light energy conversion layer containing SrZn2N2 and a second light energy conversion layer containing an light energy conversion material. The light energy conversion material has a narrower band gap than the SrZn2N2.