Cr-Doped Oxide Fluorescent Material for Wide Red-NIR Bandwidth
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Solution Overview
Problem
Current light emitting devices struggle to achieve a wide full width at half maximum in their light emission spectrum within the red to near-infrared wavelength range, which is essential for applications such as medical imaging, food analysis, and plant growth promotion.
Innovation Solution
An oxide fluorescent material with a specific composition, including elements like Li, Na, K, Ca, Sr, Ge, and Cr, is developed, which, when heat-treated, emits light with a peak wavelength between 700 nm and 1,050 nm and a full width at half maximum of 150 nm or more, and is used in conjunction with a light emitting element that irradiates the fluorescent material with light of 365 nm or more and 500 nm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional fluorescent material is used, then the light emission intensity in the red to near-infrared range is achieved, but the full width at half maximum of the light emission spectrum is narrow
Solution Approach 1:
The patent changes the chemical composition parameters of the fluorescent material by incorporating specific ratios of Li, Na, K, Ca, Sr, Ge, and Cr elements. By adjusting the molar ratios of these elements (particularly Ge at 6:1 and Cr at 0.2 or less), the light emission spectrum is modified to achieve both high intensity and wide full width at half maximum in the 700-1050 nm range
Solution Approach 2:
The patent creates a composite fluorescent material by combining multiple elements (Li, Na, K, Ca, Sr, Ge, Cr) in specific proportions. This composite approach allows the material to exhibit enhanced optical properties including both high light emission intensity and wide spectral width, which cannot be achieved with single-element fluorescent materials
2Adaptability or versatility
If the light emission peak wavelength is extended to near-infrared range, then the applicability to medical imaging and plant growth is improved, but the manufacturing precision of the fluorescent material becomes more difficult
Solution Approach 1:
The patent establishes specific parameter ranges for each element composition to achieve near-infrared emission at 700-1050 nm. By controlling the molar ratios (Ge: 6, Cr: 0.2 or less, Li: 1.5-2.5, Ca: 0.7-1.3), the manufacturing process achieves consistent results with reduced complexity despite the extended wavelength range requirements
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 solution provides a light emitting device with a wide emission spectrum suitable for various applications, including medical imaging and plant growth, by enhancing light emission characteristics and achieving efficient light transmission through biological tissues and plants.
Implementation Method 1
a light emitting device including the oxide fluorescent material and a light emitting element having a light emission peak wavelength of 365 nm or more and 500 nm or less to irradiate the oxide fluorescent material with light
Implementation Method 2
heat-treating the raw material mixture at a temperature 900° C. or higher and 1,200° C. or lower in an atmosphere containing oxygen to obtain an oxide fluorescent material
Data Source
AI summary
Provided is an oxide fluorescent material having a light emission peak in a wavelength range from red light to near-infrared light.The oxide fluorescent material has a composition including: a first element M1 being at least one element selected from the group consisting of Li, Na, K, Rb, and Cs; a second element M2 being at least one element selected from the group consisting of Ca, Sr, Mg, Ba, and Zn; Ge; O (oxygen); and Cr, the composition optionally including: a third element M3 being at least one element selected from the group consisting of Si, Ti, Zr, Sn, Hf, and Pb; and a fourth element M4 being at least one element selected from the group consisting of Eu, Ce, Tb, Pr, Nd, Sm, Yb, Ho, Er, Tm, Ni, and Mn. When the molar ratio of Ge, or the total molar ratio of the third element M3 and Ge in the case of comprising the third element M3, in 1 mol of the composition of the oxide fluorescent material is 6, the molar ratio of the first element M1 is 1.5 or more and 2.5 or less, the molar ratio of the second element M2 is 0.7 or more and 1.3 or less, the molar ratio of the third element M3 is 0 or more and 0.4 or less, the molar ratio of O (oxygen) is 12.9 or more and 15.1 or less, and the molar ratio of Cr is 0.2 or less. The oxide fluorescent material has a light emission peak wavelength of 700 nm or more and 1,050 nm or less in a light emission spectrum of the oxide fluorescent material.