Codoped Perovskite Halide Scintillators for Reduced Afterglow
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Solution Overview
Problem
There is a need for optical materials with improved scintillation properties, such as enhanced energy resolution and reduced afterglow, to meet the demands of various applications including medical imaging and nuclear detection, as existing materials face challenges in fast response times and radioisotope identification.
Innovation Solution
The development of codoped metal halide optical materials, specifically perovskite-type halides with a formula ABX3, doped with europium and codoped with trivalent ions like scandium, yttrium, or gadolinium, which modify afterglow and scintillation properties, are used in radiation detectors to enhance light yield and energy resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional scintillator materials are used, then basic radiation detection function is provided, but afterglow is excessive and energy resolution is insufficient
Solution Approach 1:
The patent applies parameter changes by systematically varying the composition parameters of the perovskite-type halide material. Specifically, it adjusts the doping concentration of europium (Eu²⁺) and the codoping concentration of trivalent ions (Sc³⁺, Y³⁺, or Gd³⁺) to optimize both energy resolution and afterglow characteristics. The formula ABX3 with specific compositional ranges (0 < x ≤ 0.1 for Eu doping, 0 < y ≤ 0.05 for trivalent ion codoping) represents controlled parameter modification to achieve superior scintillation performance.
Solution Approach 2:
The patent employs composite materials by creating a doped perovskite-type halide structure where europium ions and trivalent ion dopants are incorporated into the ABX3 crystal lattice. This composite approach combines the host material's fast response characteristics with the dopant's luminescent properties, resulting in a material that simultaneously achieves reduced afterglow and improved energy resolution for gamma ray and X-ray detection.
2Speed
If fast response time is prioritized in scintillator selection, then medical imaging applications are improved, but radioisotope identification capability deteriorates
Solution Approach 1:
The patent resolves this contradiction through parameter changes by optimizing the doping concentrations to achieve a balanced performance profile. The specific compositional parameters (Eu doping level x, trivalent ion doping level y) are tuned to provide both fast response time for medical imaging and sufficient light yield with good energy resolution for radioisotope identification, eliminating the need to choose between these competing requirements.
Solution Approach 2:
The patent achieves universality by developing a perovskite-type halide scintillator material that can serve multiple functions across different application domains. The codoped material structure enables the same material to perform both fast response detection for medical imaging and high precision energy measurement for nuclear material identification, making it a multi-functional scintillator suitable for diverse radiation detection needs.
3Quantity of substance
If existing scintillator materials are used, then basic detection capability is provided, but light yield and energy resolution performance are insufficient
Solution Approach 1:
The patent applies composite materials by incorporating europium dopants and trivalent ion codopants into the perovskite-type halide lattice. This composite structure enhances light yield through the dopant's efficient luminescence while simultaneously improving energy resolution through the modified crystal field and reduced phonon interactions, achieving both high light output and precise energy measurement capabilities.
Solution Approach 2:
The patent utilizes parameter changes by systematically adjusting the dopant concentrations (europium content x and trivalent ion content y) to optimize the balance between light yield and energy resolution. The specific compositional parameters are selected to maximize photon production while maintaining the crystal structure's ability to provide accurate energy discrimination, thereby improving both quantity and quality of detection signal.
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
These codoped materials demonstrate reduced afterglow, improved scintillation decay times, and increased light yield, effectively addressing the limitations of existing scintillators by providing enhanced performance in detecting gamma rays and X-rays with improved energy resolution.
Implementation Method 1
Optical materials include phosphors and scintillators, which can emit light pulses in response to impinging radiation, such as X-rays, gamma rays, and neutrons
Implementation Method 2
the presently disclosed subject matter relates to their optical (e.g., scintillation and phosphorescence properties), and their use as persistent phosphors
Data Source
AI summary
Metal halide optical materials (e.g., scintillator materials or persistent phosphors) are described. More particularly, the optical materials include codoped perovskite-type halides, wherein the codoping ion is present at a molar ratio of 5000 parts per million (ppm) or less with respect to all cations. For example, the optical material can be a codoped trihalide having the formula ABX3 where A is one or more alkali metal, B is one or more alkali earth metal, and X is one or more halide that is doped with up to about 10 atomic percent of a dopant ion and codoped with up to about 5000 ppm of one or more isovalent or aliovalent codopant ion, such as a tetravalent ion (e.g., Zr4+), a trivalent ion (e.g., Sc3+, Y3+, Gd3+, or La3+ ion) or a divalent ion (e.g., Mg2+). The codoped material can have modified afterglow compared to a noncodoped material.