Elongated Seed Quantum Dots for Thermal Stability
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Solution Overview
Problem
Conventional quantum dots exhibit significant thermal and flux droop, leading to a decrease in photoluminescence quantum yield with increasing temperatures and light intensities, which affects their luminescence performance.
Innovation Solution
A semiconductor structure comprising an elongated seed particle with a high aspect ratio, encapsulated in a shell of a larger bandgap semiconductor material, which maintains a high photoluminescence quantum yield across various temperatures and light fluxes, with the seed particle arranged either centered or off-center within the shell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional quantum dots are used, then they can be prepared to luminesce in a particle-size-dependent fashion, but they exhibit pronounced thermal and flux droop leading to significant decrease of photoluminescence quantum yield with increasing temperatures and incident light intensities
Solution Approach 1:
The patent changes the morphological parameter of the seed particle from conventional shapes to an elongated shape with high aspect ratio (greater than 1.5). This parameter change in geometry fundamentally alters the thermal and flux droop characteristics, enabling the quantum dot to maintain high photoluminescence quantum yield (at least 65%) across a wide temperature range (20°C to 150°C) and high excitation light fluxes (up to 150 W/cm²) without significant degradation
Solution Approach 2:
The patent employs a core-shell composite structure where the core consists of the elongated seed particle and the shell comprises a larger bandgap semiconductor material. This composite architecture combines the advantageous optical properties of the elongated seed with the protective and passivating effects of the shell material, resulting in enhanced thermal stability and resistance to luminescence quenching at high temperatures and light intensities
2Reliability
If conventional quantum dots are used, then they can be prepared to luminesce in a particle-size-dependent fashion, but they exhibit pronounced flux droop leading to significant decrease of photoluminescence quantum yield with increasing incident light intensities
Solution Approach 1:
The patent changes the morphological parameter of the seed particle from conventional shapes to an elongated shape with high aspect ratio (greater than 1.5). This parameter change in geometry fundamentally alters the flux droop characteristics, enabling the quantum dot to maintain high photoluminescence quantum yield (at least 65%) across a wide range of excitation light fluxes (up to 150 W/cm²) without significant degradation
Solution Approach 2:
The patent employs a core-shell composite structure where the core consists of the elongated seed particle and the shell comprises a larger bandgap semiconductor material. This composite architecture combines the advantageous optical properties of the elongated seed with the protective and passivating effects of the shell material, resulting in enhanced resistance to luminescence quenching at high light intensities
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 semiconductor structure achieves a photoluminescence quantum yield of at least 65% across a temperature range of 20° C. to 150° C. and excitation light fluxes up to 150 W/cm², with minimal deviation, demonstrating superior resilience to luminescence quenching even at high optical fluxes and temperatures.
Implementation Method 1
the semiconductor structure, in particular the seed particle, produces photoluminescence emission when being irradiated with an excitation light
Data Source
AI summary
A semiconductor structure and a light-emitting device having a light-emitting diode and a plurality of semiconductor structures are disclosed. In an embodiment, the semiconductor structure includes an elongated seed particle including a first semiconductor material, wherein the seed particle has an aspect ratio of greater than 2.0, and wherein the semiconductor structure is part of or forms a quantum dot.