Dynamic Reflective Surface Grating for Solar Cell Light Trapping
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Solution Overview
Problem
Next-generation solar cells, such as organic photovoltaic cells, face efficiency limitations due to weak light absorption, which can be addressed by increasing the active layer thickness, but this results in fewer charge carriers reaching the electrodes, and static surface relief gratings are not optimized for varying light conditions throughout the day and season.
Innovation Solution
A solar cell system with a reflective surface and a movement unit that dynamically adjusts its geometry in response to changing light conditions by actuating movement members to deform the reflective surface, optimizing light absorption and device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the active layer thickness is increased to compensate for weak light absorption, then light absorption is improved, but fewer charge carriers successfully reach their respective electrodes
Solution Approach 1:
The patent applies dynamics by making the surface relief grating geometry changeable rather than static. The grating structure can adapt its configuration to optimize light absorption under varying illumination conditions, thereby maintaining effective light trapping without requiring increased active layer thickness that would harm charge carrier transport.
2Illumination intensity
If static surface relief gratings are used to enhance light absorption, then light absorption is improved, but optimal conditions are only met for one instant on one day per year
Solution Approach 1:
The patent transforms the static SRG into a dynamic structure that can adjust its geometry in response to changing light conditions. This allows the grating to maintain optimal light absorption performance across varying angles of incidence, times of day, and seasonal changes, thereby resolving the contradiction between achieving high light absorption and maintaining adaptability.
3Illumination intensity
If the SRG geometry is optimized for a given set of conditions, then light absorption is maximized for those conditions, but the solar module cannot adapt to broad ranges of incident angles and environmental changes
Solution Approach 1:
The patent implements a dynamic SRG that can actively adjust its geometry to optimize light absorption across a broad range of incident angles and environmental conditions. This dynamic adaptability allows the system to maintain high light absorption efficiency whether the sun is at a low or high angle, regardless of time of day or season.
Solution Approach 2:
The patent applies parameter changes by modifying the geometric parameters of the surface relief grating (such as period, depth, or profile) in response to changing environmental conditions. These parameter adjustments enable the grating to maintain optimal optical performance across varying illumination scenarios without sacrificing adaptability.
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 dynamic adjustment of the reflective surface enhances light absorption and maintains optimal performance across varying light conditions, improving the efficiency and commercial viability of solar cells by adapting to different angles of incidence and environmental changes.
Implementation Method 1
a reflective electrode reflects light that enters the solar cell and allows it additional opportunities to be absorbed by the solar cell
Implementation Method 2
Periodic, sub-micrometer substrate structures can trap light within the active layer by reflecting it at higher angles back through the film rather than letting it reflect straight out of the device
Implementation Method 3
The output of the controller of the movement unit is coupled to the movement member such that the controller actuates the movement member to apply a force to at least a portion of the bottom face of the reflective surface
Data Source
AI summary
A solar cell system is formed with a dynamic surface relief grating. Movement members are actuated by a controller to produce a force on the reflective surface. The reflective surface deforms in response to the force creating a surface relief grating that can adapt to changing light conditions.