CdTe-Matched Silicate Glass for PV Modules
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Solution Overview
Problem
Current glass compositions used in semiconductor applications, such as photovoltaics and OLEDs, face challenges including high manufacturing costs, excessive temperatures leading to asset deterioration, and incompatibility with CdTe-based thin film PV modules due to sodium-related issues, which affect efficiency and device lifetime.
Innovation Solution
Development of glass compositions with specific molecular percentages of SiO2, Al2O3, B2O3, M2O, RO, and additional components like SnO2, tailored to match the coefficient of thermal expansion (CTE) of CdTe thin films, optimizing thermal stability and reducing residual stress for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-silica glass compositions (e.g., 1737, Eagle 2000, Jade, Gorilla Glass) are used to achieve optimal surface and geometric characteristics for electronics applications, then manufacturing precision and reliability are improved, but manufacturing cost increases due to high melting temperatures (>1600°C) and viscosity requiring accelerated asset deterioration and frequent rebuilds
Solution Approach 1:
The patent modifies the chemical composition parameters of the glass, specifically reducing silica content from >90% to 60-65 mol% and adding boron oxide (7-15 mol%), alkaline earth metals (9-15 mol% RO), and controlled alkali metals (0-8 mol% M2O). These parameter changes lower the melting temperature and viscosity while maintaining the required surface and geometric characteristics through optimized CTE matching.
Solution Approach 2:
The invention creates a composite glass system combining multiple oxide components (SiO2, B2O3, Al2O3, RO, M2O) in specific proportions. This composite composition achieves the desired mechanical and optical properties while reducing manufacturing complexity and cost compared to high-silica formulations, particularly by incorporating boron to lower melting temperature and improve flow characteristics.
2Reliability
If high melting temperature glass compositions are used to achieve desired glass properties, then reliability is improved, but productivity decreases due to slow melt rates and accelerated asset deterioration
Solution Approach 1:
The patent changes the compositional parameters to include boron oxide (7-15 mol%) and alkaline earth metals (9-15 mol% RO), which significantly reduce the melting temperature and viscosity. This enables faster melt rates and improved productivity while maintaining reliability through optimized CTE matching (4.0-7.5 ppm/°C) that ensures proper thermal expansion compatibility with semiconductor substrates.
3Ease of manufacture
If conventional soda lime glass is used for PV panels to reduce cost, then manufacturing cost decreases, but reliability worsens due to sodium release causing efficiency degradation and delamination
Solution Approach 1:
The patent modifies the glass composition by limiting alkali metal oxides (M2O) to 0-8 mol% and specifically controlling sodium content, while increasing alkaline earth metals (RO) to 9-15 mol%. This reduces sodium release that causes delamination and efficiency degradation in PV modules, improving reliability while maintaining cost-effectiveness compared to high-silica glasses. The CTE matching (4.0-7.5 ppm/°C) further enhances reliability by reducing thermal stress.
4Stability of the object's composition
If high-silica glass compositions are used to achieve low CTE, then stability is improved, but ease of manufacture worsens due to high viscosity requiring expensive fining solutions
Solution Approach 1:
The patent optimizes the composition parameters by adding boron oxide (7-15 mol%) and alkaline earth metals (9-15 mol% RO), which reduce viscosity and improve fining characteristics. The CTE is maintained within the stable range of 4.0-7.5 ppm/°C through balanced composition, achieving both stability and ease of manufacture without requiring expensive arsenic-based fining agents or vacuum fining 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
The tailored glass compositions reduce manufacturing costs, enhance thermal stability, and minimize residual stress in CdTe films, leading to improved conversion efficiency and extended device lifetime by matching CTE, thus making them suitable for large-area photovoltaic panels and OLED lighting.
Implementation Method 1
optimized to have a coefficient of thermal expansion (CTE) matching that of CdTe thin-film photovoltaic modules, reducing residual stress
Data Source
AI summary
CTE-matched silicate glasses and more particularly to low-alkali CTE-matched silicate glasses that are useful in semiconductor-based applications, such as photovoltaics are described along with methods of making such glasses.