InP Nanoparticles with ZnSeTe Shell for Blue Light Absorption
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Solution Overview
Problem
Semiconductor nanoparticles used in QD patternings for displays have a limited absorption coefficient due to their thickness, leading to mixed colors when blue light passes through, and existing shell materials that can absorb blue light are toxic, such as CdZnSeS.
Innovation Solution
InP-based semiconductor nanoparticles with a core-shell structure using ZnSeTe, ZnSTe, or ZnSeSTe as shell materials, which have a controlled band gap to enhance blue light absorption without using toxic cadmium, resulting in a higher absorption coefficient and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional shell materials (CdZnSeS) are used to increase blue light absorption, then absorption coefficient is improved, but toxicity increases due to cadmium content
Solution Approach 1:
The patent changes the compositional parameters of the shell material by using ZnSeTe, ZnSTe, or ZnSeSTe instead of Cd-containing materials. By adjusting the ratios of Se and Te (where Te/(Se+Te)=0.03 to 0.50), the band gap is optimized to enhance blue light absorption while maintaining non-toxicity. This parameter change resolves the contradiction by achieving high absorption coefficient through compositional optimization rather than using toxic cadmium.
Solution Approach 2:
The patent employs composite shell structures with multiple materials (ZnSeTe, ZnSTe, or ZnSeSTe) that combine the advantages of different chalcogenides. These composite materials provide both high blue light absorption capability and non-toxicity, replacing the single-material CdZnSeS approach. The composite structure allows tuning of optical properties while maintaining safety.
2Reliability
If shell thickness is increased to improve stability, then stability is improved, but absorption coefficient decreases due to large band gap of conventional shell materials
Solution Approach 1:
The patent changes the fundamental parameter of the shell material's band gap by selecting materials (ZnSeTe, ZnSTe, ZnSeSTe) with appropriate band gaps for blue light absorption. This allows the shell to simultaneously provide stability through sufficient thickness while maintaining high absorption coefficient, as the materials inherently possess the right optical properties unlike conventional wide-band-gap materials.
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 nanoparticles achieve a high absorption coefficient for blue light, maintaining stability and preventing mixed colors in thin QD patternings, while being free from toxic cadmium, thus enhancing display color accuracy and safety.
Implementation Method 1
shell materials having an appropriate band gap, but known shell materials capable of absorbing blue light contain Cd
Implementation Method 2
Semiconductor nanoparticles so small as to induce a quantum confinement effect have band gaps that depend on particle size
Implementation Method 3
Excitons formed within the semiconductor nanoparticles by some means, such as photoexcitation or charge injection, recombine to release photons of energy corresponding to the band gap
Implementation Method 4
Excitons formed within the semiconductor nanoparticles by some means, such as photoexcitation or charge injection, recombine to release photons of energy corresponding to the band gap
Data Source
AI summary
The purpose of the present invention to provide semiconductor nanoparticles substantially containing no Cd, and which have an increased absorption coefficient to blue light while maintaining high stability. Semiconductor nanoparticles having a core containing at least In and P, and a shell having one or more layers, wherein at least one layer of the shell is ZnSeTe (wherein Te/(Se+Te)=0.03 to 0.50); and the semiconductor nanoparticles cause, when the semiconductor nanoparticles are dispersed in a dispersion medium to yield a dispersion liquid with a concentration of 1 mg/mL in inorganic mass, the dispersion liquid to have an absorbance of 0.9 or higher with respect to light having a wavelength of 450 nm at an optical path length of 1 cm.