Photovoltaic Device Nonlinear Multi-Photon Absorption
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Solution Overview
Problem
Current photovoltaic devices are limited by the Shockley-Queisser limit, which restricts energy conversion efficiency from black-body radiation to approximately 31% for single p-n junction solar cells, and increasing intensity concentration degrades materials, while existing multi-junction and nonlinear absorption methods have not achieved high efficiency due to material limitations and inefficiencies.
Innovation Solution
A method utilizing nonlinear multi-photon absorption in semiconductor bodies with a predetermined bandgap, subjected to incoherent radiation and magnetic or electric fields, to generate electrical power by converting photons with energy below the bandgap, enhancing efficiency through increased absorption rates and transition probabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single p-n junction solar cells are used, then device simplicity is maintained, but energy conversion efficiency is limited to approximately 31% due to the Shockley-Queisser limit
Solution Approach 1:
The patent changes the fundamental absorption parameter from single-photon to multi-photon absorption, enabling the semiconductor body to absorb photons with energies below the bandgap when illuminated with high-intensity concentrated light. This parameter change allows efficient utilization of the entire solar spectrum while maintaining a single p-n junction structure, thereby improving energy conversion efficiency without increasing device complexity
Solution Approach 2:
The patent segments the solar spectrum utilization by having different portions of the incident light spectrum absorbed through different photon combination processes (two-photon absorption, three-photon absorption, etc.), with each process contributing to electron-hole pair generation in the single semiconductor body, thus achieving high efficiency without multiple junctions
2Use of energy by moving object
If light intensity concentration is increased to enhance efficiency, then energy conversion efficiency improves, but material degradation occurs
Solution Approach 1:
The patent changes the absorption mechanism from linear single-photon absorption to nonlinear multi-photon absorption, which has a different intensity dependence. The multi-photon absorption coefficient has a higher threshold for material damage while maintaining efficient energy conversion at operational intensities, thus improving efficiency without causing material degradation
Solution Approach 2:
The patent utilizes the temporal coherence properties of laser illumination to create periodic electromagnetic field cycles that drive multi-photon absorption events, allowing the material to recover between cycles and avoid cumulative damage that would occur with continuous high-intensity irradiation
3Productivity
If photons with energy below the bandgap are used, then broader spectrum utilization is achieved, but absorption probability is insufficient in conventional single-photon processes
Solution Approach 1:
The patent merges multiple low-energy photons (each below the bandgap) into a combined energy state that exceeds the bandgap, enabling electron-hole pair generation. This merging process allows the semiconductor to utilize photons across the entire solar spectrum including infrared regions that are normally transparent to conventional solar cells, thus achieving broad spectrum utilization with high absorption probability
Solution Approach 2:
The patent employs semiconductor materials with specific bandgap energies optimized for multi-photon absorption of solar spectrum photons, combining the properties of direct bandgap semiconductors with appropriate carrier mobility and lifetime characteristics to achieve high efficiency conversion of sub-bandgap photons through nonlinear optical processes
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 potentially increases energy conversion efficiency beyond traditional limits by effectively capturing a broader spectrum of radiation, reducing material degradation, and increasing carrier generation rates, thereby improving the overall performance of photovoltaic devices.
Implementation Method 1
converting incoherent broad spectral band optical energy in a body into electrical power using nonlinear multi-photon absorption process
Implementation Method 2
an optical system having a bandpass optical filter for directing incoherent radiation... to an interior region of the body... the intensity in the body being sufficient to operate the body in a nonlinear multi-photon absorption mode
Implementation Method 3
a bandpass optical filter for directing incoherent radiation... within a predetermined band of frequencies
Data Source
AI summary
Methods, systems, and photovoltaic devices converting broad spectrum incoherent optical power into electrical power by utilizing nonlinear multi-photon absorption and optionally enhanced by the application of magnetic fields, electric fields, or both during the power conversion process.