Hexagonal 6H Barium Germanium Oxide Transparent Conductor
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Solution Overview
Problem
Current transparent conductive materials for mobile information terminals, such as smartphones and tablets, rely heavily on rare metals like indium oxide, prompting the need for alternative materials that utilize abundant resources like barium and germanium to achieve a suitable band gap for conductivity.
Innovation Solution
A barium germanium oxide with a hexagonal 6H-type perovskite structure is developed, processed at high temperatures and pressures, incorporating specific lattice constants and dopants to achieve a band gap of 2.5 eV to 4 eV, enabling its use as a transparent conductive substance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If barium germanium oxide with perovskite structure is synthesized using abundant resources (Ba and Ge), then resource availability is improved, but the material becomes amorphous at atmospheric pressure and cannot be utilized as transparent conductive substance
Solution Approach 1:
The patent applies high pressure (9.5-12 GPa) and high temperature (650-1400°C) processing conditions to transform the crystal structure of barium germanium oxide from amorphous or unstable phases to stable hexagonal 6H-type perovskite structure that maintains its crystalline form at atmospheric pressure. This parameter change approach resolves the contradiction by finding specific synthesis conditions that enable both resource utilization and structural stability.
Solution Approach 2:
The patent utilizes phase transition mechanisms by processing barium germanium oxide through controlled heating and pressurization to transform it from pseudo-wollastonite structure to hexagonal 6H-type perovskite structure. This phase transition approach allows the material to achieve a stable crystalline state that can be maintained at atmospheric pressure, resolving the amorphization issue while using abundant Ba and Ge resources.
2Reliability
If hexagonal 6H-type barium germanium oxide is synthesized at high pressure and temperature, then crystal structure stability is improved, but the synthesis process complexity increases
Solution Approach 1:
The patent employs preliminary preparation of raw materials with specific composition ratios and pre-mixing procedures before subjecting them to high pressure and temperature treatment. This preliminary action simplifies the overall process by ensuring proper material distribution and chemical readiness before the complex phase transition, reducing potential synthesis failures and simplifying the operational complexity.
3Reliability
If band gap is reduced to 4 eV or less for transparent conductive application, then electrical conductivity is improved, but the material may lose transparency
Solution Approach 1:
The patent achieves the optimal balance between conductivity and transparency by precisely controlling the band gap to be 4 eV or less through composition optimization and crystal structure control. The hexagonal 6H-type perovskite structure with specific lattice parameters (a=0.56006±0.05 nm, b=0.56006±0.05 nm, c=1.3653±0.1 nm) enables this parameter optimization, allowing the material to maintain both transparency and conductive performance.
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 barium germanium oxide with a 6H-type perovskite structure maintains stability under atmospheric pressure and can be used as a transparent conductive material by controlling dopants and defects, offering a viable alternative to rare metal-based materials.
Implementation Method 1
the crystal represented by ABO3 may have a hexagonal 6H-type perovskite structure... maintains stability under atmospheric pressure
Implementation Method 2
BaGeO3 of 9H type is synthesized by processing an oxide represented by BaGeO3 having a pseudo-wollastonite structure in a temperature range from 650 degree Celsius to 850 degree Celsius and in a pressure range from 9.5 GPa to 12 GPa
Data Source
AI summary
Provided are a barium germanium oxide having a 3-4 eV band gap, a method for producing the same, a sintered body thereof, and a target thereof. The barium germanium oxide includes at least Ba, Ge, and O, includes a crystal represented by a general formula of ABO3 (here, A includes at least Ba and B includes at least Ge), and has a hexagonal 6H-type perovskite structure.