Aluminum Hydroxide Wavelength Conversion Layer for Silicon Solar Cells
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Solution Overview
Problem
Commercially available silicon solar cells suffer from inefficiencies due to mismatched band gaps with the natural solar spectrum, leading to parasitic absorption, thermal loss, and reflection, which limits their ability to utilize the entire solar spectrum effectively.
Innovation Solution
The integration of a low-cost, aluminum-based luminescent hydroxide as a solar wavelength conversion material on the interface between the solar cell and encapsulant, which acts as a down-conversion material, enhancing the absorption of ultraviolet rays and converting them into visible light, thereby improving photocurrent conversion efficiency and reducing reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a silicon solar cell is used to manufacture solar cells, then the manufacturing cost is low and the manufacturing process is mature, but the photoelectric conversion efficiency is limited due to band gap mismatch with the solar spectrum
Solution Approach 1:
The patent combines silicon solar cells with aluminum-based luminescent hydroxide material to create a composite structure. The aluminum-based material converts ultraviolet light into visible light wavelengths that match the silicon band gap, enabling the silicon cell to utilize previously unusable UV portion of the solar spectrum while maintaining the simplicity and low cost of silicon-based manufacturing
Solution Approach 2:
The patent changes the optical parameters of the solar cell system by introducing a wavelength conversion layer. This layer transforms the incident light spectrum parameters (converting UV wavelengths to visible wavelengths), allowing the silicon solar cell to absorb a broader range of solar radiation and improve photoelectric conversion efficiency without changing the silicon cell structure itself
2Productivity
If a down-conversion material is positioned on the front surface of the solar cell, then the absorption of ultraviolet rays is enhanced and visible light is produced, but the reflection loss and parasitic absorption still occur
Solution Approach 1:
The aluminum-based luminescent hydroxide material acts as an intermediary between the incident solar radiation and the silicon solar cell. It first absorbs ultraviolet photons, then emits visible light photons that are optimally absorbed by the silicon cell, mediating the energy transfer and reducing direct reflection losses at the silicon surface
Solution Approach 2:
The patent converts the previously harmful effect of ultraviolet radiation (which caused thermalization losses when directly incident on silicon) into a beneficial effect by using the aluminum-based material to convert UV photons into visible photons that can be efficiently converted to electricity by the silicon cell
3Productivity
If the solar wavelength conversion material is positioned on the interface between solar cell and encapsulant, then the down-conversion effect and anti-reflective coating effect are achieved simultaneously, but the material positioning precision must be high
Solution Approach 1:
The aluminum-based luminescent hydroxide material positioned at the interface between the solar cell and encapsulant performs multiple functions simultaneously: it acts as a down-conversion material converting UV to visible light, and as an anti-reflective coating reducing reflection losses. This multi-functionality maximizes the benefit of the material placement while simplifying the overall device structure
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 increases the short-circuit current and overall photoelectric conversion efficiency of silicon solar cells, reduces the unit cost of photovoltaic power generation, and provides an anti-potential induced degradation (PID) effect, enhancing the competitiveness of solar cells by effectively utilizing a wider range of the solar spectrum and minimizing losses.
Implementation Method 1
the down-conversion is a technique of absorbing one photon of a short wavelength with higher energy than the silicon band gap (for example, a wavelength of ultraviolet ray) to convert the absorbed photon into one or two or more photons in a long-wavelength area with low energy in which silicon is capable of absorbing light well
Implementation Method 2
an anti-reflective coating effect in which light easily enters the inside of the silicon solar cell along with a down-conversion effect when using luminescent aluminum hydroxide
Implementation Method 3
improving photocurrent conversion efficiency by absorbing an ultraviolet-ray of solar spectrum in which it is difficult to absorb light into silicon into the solar wavelength conversion material, and then down-converting the absorbed solar spectrum into light in a visible-ray in which light is easily absorbed into silicon
Data Source
AI summary
When a solar wavelength conversion material (solar spectral wavelength converter) produced based on a low-cost aluminum material having an ultraviolet ray absorption spectrum and a visible light emitting spectrum is positioned between a solar cell and an encapsulant of the front surface of the solar cell on which solar light is incident, photocurrent conversion efficiency of the solar cell may be improved by inducing a down-conversion effect and an anti-reflective coating effect at the same time, thereby increasing light-generated current.