Multicolor Nanophosphor for Tunable Light Emission
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Solution Overview
Problem
Current nanophosphors face limitations in achieving strong and tunable light emission colors under a single excitation wavelength, with existing methods either requiring multiple excitation wavelengths or suffering from low light emission intensity and photostability issues, particularly in applications like solar cells and bioimaging.
Innovation Solution
A fluoride-based nanophosphor doped with Ce3+ and Tb3+, with optional Eu3+ as a co-doping agent, which absorbs ultraviolet light and transfers energy to emit strong green and red light, allowing for adjustable light emission colors by varying the composition ratio under a single excitation wavelength, and is synthesized using a method involving heat treatment of mixed solutions containing lanthanide and lithium compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple types of phosphors with different light emission colors are mixed, then various light emission colors can be achieved, but different excitation light sources with different wavelengths are required
Solution Approach 1:
Ce3+ ions are introduced as an intermediary energy transfer mediator that absorbs ultraviolet light around 250 nm and transfers the absorbed energy to various lanthanide elements (Tb3+, Eu3+, Sm3+, Dy3+), enabling all dopants to be excited by a single wavelength and eliminating the need for multiple excitation light sources
Solution Approach 2:
By changing the composition ratios of different lanthanide elements doped into the NaGdF4 host material, various light emission colors can be achieved while maintaining a single excitation wavelength, thus varying the emission color parameter without affecting the excitation parameter
2Illumination intensity
If the amount of co-doping agent Ce is increased to improve absorption efficiency of excitation light, then strong light emission can be obtained, but the light emission color becomes fixed and cannot be tuned
Solution Approach 1:
The composition ratios of various lanthanide elements (Tb3+, Eu3+, Sm3+, Dy3+) are adjusted to change the light emission color, while the Ce3+ content is optimized to maintain both strong absorption of excitation light and color tunability through compositional variation
3Productivity
If nanophosphor particle size is reduced to enhance solar cell efficiency by minimizing light scattering, then light scattering is reduced, but light emission intensity becomes weaker
Solution Approach 1:
A composite nanophosphor structure is created by doping multiple lanthanide elements (Ce3+ as sensitizer, Tb3+/Eu3+/Sm3+/Dy3+ as activators) into the NaGdF4 host material, achieving both strong light emission and color tunability in small particle sizes to minimize scattering while maintaining high intensity
Solution Approach 2:
Ce3+ acts as an intermediary that enhances the absorption of ultraviolet light, enabling small nanophosphor particles to achieve strong light emission intensity through efficient energy transfer from Ce3+ to the emitting lanthanide ions, thus maintaining both small size and high intensity
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 nanophosphor achieves high light emission intensity and stability, enabling efficient conversion of ultraviolet light to visible light, suitable for enhancing solar cell efficiency and providing stable bioimaging contrast without blinking, and can produce a range of colors including green, yellowish green, yellow, and orange.
Implementation Method 1
the co-doping agent Ce3+ absorbs ultraviolet light and transfers the absorbed energy to Tb3+ and Eu3+, so that light emission peaks appear in the green and red regions
Implementation Method 2
the co-doping agent Ce3+ absorbs ultraviolet light
Implementation Method 3
the nanophosphor according to the present invention follows the downconversion mechanism in which Ce absorbs ultraviolet light and Tb and Eu emit green and red peaks
Implementation Method 4
A nanophosphor according to an exemplary embodiment of the present invention includes a fluoride-based nanoparticle co-doped with Ce3+, Tb3+, and Eu3+, which absorbs ultraviolet light and transfers the absorbed energy to emit strong green and red light
Data Source
AI summary
The present invention relates to a nanophosphor which may be used as a wavelength conversion part of a solar cell, a fluorescent contrast agent, and a light emitting part of a display device, and a synthesis method thereof. The nanophosphor of the present invention is excited by ultraviolet light to exhibit strong green light emission, and has multicolor light emission characteristics capable of controlling a color such as green, yellowish green, yellow, and orange color by only adjusting the amount of a doping agent.