Core-Shell Nanoparticle Photovoltaic Converter
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Solution Overview
Problem
Existing photovoltaic converter devices using silicon quantum dots and silicon oxide dielectric material thin layers face challenges in effectively retrieving charges due to the difficulty in arranging super lattice structures and maintaining particle size variations within 10% for efficient charge retrieval.
Innovation Solution
A photovoltaic converter device with a core-shell structure is developed, where nanoparticles have a core made of semiconductor material and a shell made of dielectric material with a higher band gap, allowing for efficient charge retrieval through tunneling, improving photovoltaic conversion efficiency without the need for precise particle size control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a super lattice structure is used to enable efficient charge retrieval, then charge retrieval efficiency is improved, but device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent changes the band gap parameter of the shell material to be greater than both the matrix material and core material. This parameter change creates a type-II band alignment that forms quantum wells, enabling efficient charge retrieval through tunneling without requiring complex super lattice arrangements. The shell thickness is optimized to allow tunneling while maintaining the quantum well effect.
Solution Approach 2:
The patent employs a composite core-shell structure where the shell material has different band gap properties than both the matrix and core materials. This composite structure creates favorable energy band alignment that facilitates charge separation and retrieval, replacing the need for complex super lattice structures while maintaining high charge retrieval efficiency.
2Reliability
If quantum dots with precise particle size control (variation <10%) are used to form mini-bands, then charge retrieval efficiency is improved, but manufacturing precision requirements become extremely difficult to meet
Solution Approach 1:
The patent shifts the critical parameter for charge retrieval from particle size uniformity to band gap energy alignment. By designing the shell material with a band gap greater than both the matrix and core materials, the system achieves efficient charge retrieval through quantum well tunneling, which is less sensitive to particle size variations than mini-band formation.
Solution Approach 2:
The patent introduces a shell layer with specific local properties (band gap greater than matrix and core materials) that creates favorable energy band alignment at the core-matrix interface. This local quality change enables efficient charge retrieval through tunneling, compensating for variations in overall particle size while maintaining high charge retrieval efficiency.
3Device complexity
If a simple core structure without shell is used, then device complexity is reduced, but charge retrieval efficiency deteriorates due to unfavorable energy band alignment
Solution Approach 1:
The patent introduces a shell material with specific band gap properties (greater than both matrix and core materials) to create a composite core-shell structure. This composite design establishes favorable type-II band alignment that enables efficient charge separation and retrieval through quantum well tunneling, improving charge retrieval efficiency while maintaining relatively simple spherical nanoparticle geometry.
Solution Approach 2:
The shell acts as an intermediary layer between the core and matrix materials, mediating the energy band alignment to create favorable type-II heterostructure. This intermediary shell enables efficient charge transfer through tunneling by creating quantum wells, improving charge retrieval efficiency without significantly increasing structural complexity.
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 core-shell structure enhances photovoltaic conversion efficiency by forming quantum wells that facilitate charge retrieval, improving light absorption and reducing the complexity of arranging quantum dots in a super lattice structure.
Implementation Method 1
charges within the quantum well can be readily retrieved by tunneling through the third material
Implementation Method 2
solar cells are electric power devices that use the photo-electromotive force effect to directly convert light energy to electric power
Data Source
AI summary
A photovoltaic converter device includes a photovoltaic conversion layer containing a plurality of nanoparticles in a first material in a dispersed state, wherein the nanoparticles include a second material in particles and a third material that coats the second material, the third material having a band gap E3 that is greater than a band gap E1 of the first material, and greater than a band gap E2 of the second material.