Quantum Dot Photovoltaic Device for Infrared Energy Harvesting
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Solution Overview
Problem
Traditional solar cells face limitations in efficiently harvesting energy from heat radiation and infrared sources due to issues like charge recombination, low operating voltages, and inability to absorb energy from wavelengths beyond visible light, making them unsuitable for continuous power generation in aerospace applications.
Innovation Solution
A photovoltaic device with a quantum dot array structure that converts incident photons into electromagnetic radiation, allowing for tunable frequency emission and rectification into DC current, independent of charge carrier transport, enabling efficient energy harvesting from infrared sources below 600 degrees Celsius.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional solar cells are used to harvest energy from visible light, then electrical current can be generated, but the cells cannot absorb energy from infrared radiation or heat sources
Solution Approach 1:
The patent changes the fundamental operating parameter of the photovoltaic cell from direct charge carrier collection to electromagnetic radiation emission. By modifying the energy conversion pathway to emit photons instead of collecting charges, the system can absorb infrared radiation that would otherwise be lost, as the emission process is not limited by the bandgap constraint of traditional photovoltaic materials.
Solution Approach 2:
The patent replaces the mechanical charge transport mechanism with an electromagnetic radiation mechanism. Instead of relying on physical charge carrier movement through the solar cell structure, the system converts absorbed energy directly into emitted electromagnetic radiation, eliminating the limitations of charge transport and enabling infrared energy harvesting.
2Productivity
If traditional solar cells transport charge carriers to electrodes, then electrical power can be generated, but charge recombination occurs before reaching electrodes, limiting performance
Solution Approach 1:
The patent extracts the charge carriers from the transport pathway before they can recombine. By converting charge carrier energy into electromagnetic radiation through emission, the system removes charges from the vulnerable transport path, preventing recombination losses and improving the reliability of energy conversion.
Solution Approach 2:
The patent introduces electromagnetic radiation as an intermediary between charge carrier generation and external circuit connection. Instead of directly transporting charges to electrodes, the system uses emitted photons as a mediator to transfer energy, eliminating the recombination problem associated with charge transport.
3Use of energy by moving object
If traditional solar cells operate at low voltages (2V or less), then they can harvest visible light energy, but voltage drops of 0.4V or higher limit energy harvesting from mid-infrared to visible light
Solution Approach 1:
The patent changes the voltage parameter from being limited by bandgap energy to being determined by emission frequency. By operating in the electromagnetic radiation regime rather than direct charge collection, the system can achieve higher effective voltages for infrared energy harvesting, as the emitted photon energy corresponds to the full absorbed energy rather than being constrained by material bandgap limitations.
4Productivity
If photons with energy higher than band gap are absorbed, then charge carriers are generated, but excess energy is wasted as heat or vibrations
Solution Approach 1:
The patent converts the harmful excess energy that would normally be lost as heat into useful emitted radiation. By directing the excess energy into electromagnetic emission rather than thermal dissipation, the system transforms waste energy into a productive output, improving overall energy utilization efficiency.
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 provides a reliable and sustainable energy conversion method capable of generating power continuously, day and night, from earthshine and waste heat, with tunable frequency output suitable for aerospace environments, improving efficiency and reducing the need for energy storage.
Implementation Method 1
A photovoltaic device (PVD) having a quantum dot (QD) array structure is capable of generating charge carriers from incident photons
Implementation Method 2
An electric field generator is operable to apply an electric field to the PVD sufficient to cause the charge carriers to transition through a plurality of discrete energy states formed within a corresponding one of a conductive band and a valence band of the QD array structure to generate emitted photons radiated as an electromagnetic wave
Data Source
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AI summary
An apparatus includes a photovoltaic device (PVD) having a quantum dot (QD) array structure that is capable of performing wavelength conversion. The PVD is configured to generate charge carriers from incident photons. An electric field generator is operable to apply an electric field to the PVD. Strength of the electric field is sufficient to cause the charge carriers to transition through a plurality of discrete energy states formed within a corresponding one of a conductive band and a valence band of the QD array structure. The transition of the charge carriers through the plurality of discrete energy states enables the PVD to generate emitted photons being radiated as an electromagnetic wave. A frequency (and hence wavelength) of the emitted photons being radiated as the electromagnetic wave is tunable by configuring physical attributes of the QD array structure and controlling the electric field strength.