Core-Shell Color Conversion Particle With Stokes-Shifted Emission
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Solution Overview
Problem
Chalcogenide perovskite quantum dots exhibit high absorbance but suffer from significant light emission reabsorption loss, and reducing particle size to mitigate this loss decreases absorbance.
Innovation Solution
A color conversion particle comprising a chalcogenide perovskite core and a shell with band alignment that induces a Stokes shift, allowing high absorbance and efficient light emission while minimizing reabsorption loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the particle size is reduced to suppress reabsorption loss, then light emission efficiency is improved, but absorbance decreases
Solution Approach 1:
The particle is divided into a core and a shell with different functions. The core (chalcogenide perovskite) is responsible for light absorption and emission, while the shell (oxide perovskite) provides protective and optical optimization functions. This segmentation allows the core to maintain small size for reduced reabsorption loss while the shell compensates for absorbance and provides additional benefits
Solution Approach 2:
The invention uses a composite structure combining chalcogenide perovskite core with oxide perovskite shell. This composite material approach leverages the high absorbance and light emission properties of chalcogenide perovskite while adding the stability and optical tuning capabilities of oxide perovskite, resolving the trade-off between particle size, absorbance, and reabsorption loss
2Power
If chalcogenide perovskite is used for high absorbance and light emission efficiency, then light emission performance is improved, but light emission reabsorption loss increases
Solution Approach 1:
Different regions of the particle are assigned different properties: the core maintains high light emission efficiency characteristics of chalcogenide perovskite, while the shell provides modified optical properties with different refractive index and band structure. This local quality differentiation allows the emission region to optimize for efficiency while the surrounding shell minimizes reabsorption through optical decoupling
Solution Approach 2:
The oxide perovskite shell acts as an intermediary layer between the chalcogenide perovskite core and the external environment. This intermediary shell with its specific refractive index and optical properties mediates the optical interaction, reducing reabsorption loss while preserving the high light emission efficiency of the core material
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 achieves high absorbance and light emission efficiency with reduced reabsorption loss, leveraging the chalcogenide perovskite's large light absorption coefficient and durability.
Implementation Method 1
color conversion using wavelength conversion (downconversion) of converting excitation light incident on an object from the outside into light having a longer wavelength and emitting the light
Implementation Method 2
the core and the shell have band alignment that induces a Stokes shift
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
A color conversion particle includes a core; and a shell that contains the core and absorbs excitation light, and emits light at the core or at an interface between the core and the shell upon receiving the irradiated excitation light. The core is composed of a chalcogenide perovskite, and the core and the shell have band alignment that induces a Stokes shift.