Perovskite Quantum Dot Matrix for Stable Blue LED Emission
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Solution Overview
Problem
Existing electroluminescent materials for blue and green light-emitting diodes face challenges in achieving stable and efficient charge transport due to the absence of a perovskite matrix with a suitable band gap energy, leading to poor luminescence efficiency and material stability.
Innovation Solution
A quantum dot-in-matrix material is developed, comprising perovskite quantum dots embedded in a doped perovskite matrix, where the matrix is doped with cations like Sr to enlarge the band gap energy, and passivated with organic molecules to prevent decomposition, enabling type-I band alignment and lattice matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If perovskite quantum dots are used for high photoluminescent quantum yield, then luminescence efficiency is improved, but charge carriers become trapped at surface defect sites compromising stability
Solution Approach 1:
The patent embeds perovskite quantum dots within a perovskite matrix shell, creating a core-shell structure where the matrix nestles around the QD. This nested configuration provides surface passivation that stabilizes charge carriers while preserving the high luminescence efficiency of the embedded QDs.
Solution Approach 2:
The patent creates a composite material system combining perovskite quantum dots with a doped perovskite matrix. This composite structure integrates the high photoluminescent properties of QDs with the stability and charge transport capabilities of the matrix, achieving both improved luminescence efficiency and material stability.
2Adaptability or versatility
If quantum confinement and composition engineering are used for broad Eg tunability, then emission wavelength range is improved, but type-I band alignment requirements limit matrix selection
Solution Approach 1:
The patent utilizes composition engineering by varying the doping cation type and concentration in the perovskite matrix to tune the band gap energy. This parameter change approach enables broad emission wavelength tunability while systematically managing the band alignment requirements through controlled compositional modification.
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 material achieves high luminescence efficiency and spectral stability, allowing for efficient blue and green light emission with external quantum efficiency of 11-14% and luminance exceeding 6000 cd m−2, while overcoming lattice mismatch and hygroscopic issues.
Implementation Method 1
epitaxial growth of a perovskite matrix onto quantum dots (QDs) can enable efficient near-infrared LEDs, as it unites efficient charge transport with strong surface passivation
Implementation Method 2
Incorporation of QDs into a lead halide perovskite (APbX3) matrix has been shown to enable efficient charge transport and surface passivation
Implementation Method 3
charge transport requires a type-I band alignment between the QDs and the matrix, mandating a matrix with a Eg that is larger than that of the QDs
Implementation Method 4
passivation with organic compounds to prevent decomposition
Implementation Method 5
Light-emitting perovskite quantum dots (QDs) have shown high photoluminescent quantum yield (PLQY >90%)
Implementation Method 6
when embedded in electroluminescent devices, high external quantum efficiency (EQE >10%)
Data Source
AI summary
The present invention provides quantum dot (QD)-in-matrix materials for use in blue light emitting diodes, wherein the QD-in-matrix material comprises a plurality of quantum dots embedded in a doped lead perovskite matrix.