Free Standing Quantum Dot Photon Modulation via Voltage Control
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Solution Overview
Problem
Existing light emitting devices using free standing quantum dots (FSQDs) face challenges in controlling the photon output, which is essential for achieving desired light intensity and color modulation in applications such as displays and LEDs.
Innovation Solution
The implementation of a method to control the photon emission from FSQDs by applying a voltage potential across the device, which injects excess electrons into the FSQDs, preventing them from returning to their ground state and thus reducing emission, allowing for adjustable light intensity and color modulation by varying the voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If FSQDs are used in light emitting devices, then high quantum yield and bright displays are achieved, but control of photon output (light intensity) is problematic
Solution Approach 1:
The patent introduces an intermediary substance (oxygen-permeable polymer or oxygen plasma treatment) that mediates between the electrical excitation and the quantum dot's light emission. This intermediary allows indirect control of photon output by modulating oxygen concentration, which affects the quantum yield without directly interfering with the electrical properties of the device.
Solution Approach 2:
The patent changes the oxygen concentration parameter within the device to control light emission. By varying oxygen levels (through polymer oxygen permeability or plasma treatment), the quantum dot's emission intensity is modulated, providing a new control mechanism that complements traditional electrical control methods.
2Ease of operation
If voltage is applied to control photon emission, then light intensity modulation is achieved, but device complexity increases
Solution Approach 1:
The patent makes the polymer layer serve multiple functions: it acts as both the encapsulation/structural layer and as an oxygen control mechanism. The same polymer that provides device encapsulation also controls oxygen permeability to modulate light emission, eliminating the need for separate control mechanisms and reducing overall device complexity.
Solution Approach 2:
The device structure itself (particularly the polymer encapsulation layer) provides the control function. The polymer's inherent oxygen permeability properties enable light modulation without requiring additional active control components, allowing the device structure to serve its own control needs.
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
This approach enables precise control over the light intensity and color output of FSQD-based devices, enhancing their performance in displays and LEDs by allowing for customizable light patterns and information representation.
Implementation Method 1
The implementation of a method to control the photon emission from FSQDs by applying a voltage potential across the device, which injects excess electrons into the FSQDs, preventing them from returning to their ground state and thus reducing emission
Implementation Method 2
When a layer of FSQDs is impacted with light having a wavelength shorter that which would be emitted by the FSQDs, an electron in each of the FSQDs so impacted is excited to a higher level. When the electron falls back to its ground state, a photon is emitted
Data Source
AI summary
An apparatus is provided for modulating the photon output of a plurality of free standing quantum dots. The apparatus comprises a first electron injection layer (210, 310, 410) disposed between a first electrode (212, 312, 412) and a layer (208, 308, 408) of the plurality of free standing quantum dots. A hole transport layer (206, 306, 406) is disposed between the layer (208, 308, 408) of the plurality of quantum dots and a second electrode (204, 304, 404). A light source (224, 324, 424) is disposed so as to apply light to the layer (208, 308, 408) of the plurality of free standing quantum dots. The photon output of the layer (208, 308, 408) of the plurality of free standing quantum dots is modulated by applying a voltage to the first and second electrodes (212, 312, 412, 204, 304, 404). Electrons excited to a higher energy state within layer (208, 308, 408) of the free standing quantum dots by the light source (224, 324, 424) are prevented from returning to a lower state by electrons from the electric field of the applied voltage, and therefore the free standing quantum dots are prevented from emitting a photon. The voltage source (216, 316, 416) may be modulated to vary the photon output.