Cadmium-Free Luminescent Nanostructures for Color Conversion
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Solution Overview
Problem
Current cadmium-free luminescent nanostructures for display devices face challenges in achieving high blue light absorption and luminous efficiency, leading to issues like blue light leakage and decreased color reproducibility, while also suffering from poor chemical and thermal stability.
Innovation Solution
A luminescent nanostructure composition comprising a Group III-V compound, such as indium phosphorus, and a zinc chalcogenide, like zinc selenium sulfide, with a core-shell structure and optimized mole ratios, including fluorine, to enhance light absorption and stability, and a method for producing these nanostructures involving controlled thermal treatment and precursor addition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If cadmium-free luminescent nanostructures are used, then environmental safety is improved, but blue light absorption and luminous efficiency deteriorate
Solution Approach 1:
The patent employs a core-shell composite structure where the core contains Group III-V compound semiconductor nanocrystals (cadmium-free) and the shell contains zinc chalcogenide semiconductor nanocrystals. This composite architecture enables the cadmium-free core to provide environmental safety while the zinc chalcogenide shell enhances blue light absorption and luminous efficiency, resolving the contradiction between environmental safety and optical performance
Solution Approach 2:
The patent optimizes the mole ratio of elements (Group III:Group V:zinc chalcogenide) and controls particle size parameters to achieve maximum blue light absorption and luminous efficiency in cadmium-free nanostructures. By adjusting these parameters, the patent maintains high optical performance while eliminating cadmium, thus resolving the contradiction between environmental safety and luminous efficiency
2Object-affected harmful factors
If cadmium-free luminescent nanostructures are used, then environmental safety is improved, but chemical and thermal stability deteriorate
Solution Approach 1:
The zinc chalcogenide shell in the core-shell composite structure provides enhanced chemical and thermal stability to the cadmium-free Group III-V core. The shell acts as a protective layer that improves reliability while maintaining the environmental safety benefits of being cadmium-free, thus resolving the contradiction between environmental safety and stability
Solution Approach 2:
The patent incorporates the zinc chalcogenide shell as a protective barrier before the nanostructure is exposed to harsh chemical or thermal environments. This beforehand cushioning protects the cadmium-free core from degradation, ensuring chemical and thermal stability while maintaining environmental safety
3Manufacturing precision
If blue light absorption is increased, then color reproducibility is improved, but blue light leakage is reduced
Solution Approach 1:
The patent optimizes the composition ratios (Group III:Group V:zinc chalcogenide in a mole ratio of 1:1:0.5 to 1:1:2) and particle size parameters to achieve maximum blue light absorption. This parameter optimization enables high color reproducibility while minimizing blue light leakage, thus resolving the contradiction between color accuracy and light leakage control
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 nanostructures exhibit improved optical properties, including increased blue light absorption and luminous efficiency, while maintaining stability even in composite form, effectively addressing the limitations of existing cadmium-free nanostructures.
Implementation Method 1
A luminescent nanostructure may exhibit different aspects, characteristics, or properties than a corresponding bulk material having substantially the same composition, for example in terms of some of its physical properties (e.g., a bandgap energy, a luminescent property, and the like)... Luminescent nanostructure(s) may be configured to emit light on excitation by an energy such as an incident light
Implementation Method 2
The luminescent nanostructures of an embodiment may exhibit improved optical properties (e.g., improved blue light absorption rate and luminous efficiency)
Data Source
AI summary
A color conversion panel that includes a color conversion layer including one or more color conversion regions, and optionally, a partition wall defining the regions of the color conversion layer, and a display device including the same. The color conversion region includes a first region corresponding to a first pixel, and the first region includes a first composite including a matrix and a plurality of luminescent nanostructures dispersed in the matrix. The luminescent nanostructures include a first semiconductor nanocrystal including a Group III-V compound and a second semiconductor nanocrystal including a zinc chalcogenide. The Group III-V compound includes indium, phosphorus, and optionally, zinc or gallium, or zinc and gallium, and the zinc chalcogenide includes zinc, selenium, and sulfur. The luminescent nanostructures do not include cadmium. The luminescent nanostructures further include fluorine, and in the luminescent nanostructures, a mole ratio of fluorine to indium is greater than or equal to about 0.05:1.