3D Solar Cell Systems
3D solar cell systems are based on the treatment of the reflection of sunlight on the surface of the solar cell where the reflection of sunlight on the surface of a silicon cell is over 30 % (view graph).
This percentage represents a loss in efficiency even anti-reflection coating of light does not prevent the reflection by a large margin, and also increases the cost of the cell manufacturing, so the solution was the triangular form to catching photons reflected. There are many ideas and designs for the 3D solar cells I will subtract some of them with my ideas.
3D Solar panels
MIT researchers have discovered that the 3D modules increase the efficiency of solar panels, effectively producing up to 20 times the solar output of traditional flat panels with the same surface area. Through the construction of 3D vertical towers, scientists were able to create 3 different modules that are far more efficient in tracking solar movement and adjusting to changing seasons.
Unlike traditional flat panels that are designed to harness energy when the sun is at its peak, the different permutations were able to track the sun when it was closer to the horizon; consequently, they collected more sunlight and reflections of light in the tower and generated a more consistent output of energy over time.
Even variations in weather and altering seasons did not deter these 3D modules, as they were still able to produce double the energy of flat panels despite unfa- vorable conditions.
3D Micro solar cells
Inspired by light management techniques used in fiber optic devices, innovative solar cell are used 3-dimensional design to trap sunlight inside micro-photovoltaic structures where photons bounce around until they are converted into electrons – resulting in very high efficiency and light collection throughout the day.
- is significantly more efficient
- Can collect light from wide angles
- Solar cell that will deliver more electricity at a substantially reduced cost per kilowatt hour.
3D Nanoscale Solar Cells
The 3-D geometry enables optimization of carrier collection and reduction of the material quality constraints. Furthermore, the anti-reflective and light trapping properties enable a drastic reduction in material necessary to absorb the majority of the incident light. Together, the optical and electronic advantages allow solar cell fabrication on low-cost substrates.
However, the choice of the material system is important for taking advantage of the unique properties of nanopillar cells, especially given large surface/interface area. There has been extensive research into using nanostructured materials, such as silicon and gallium arsenide nanowires.
Although these materials have been widely used for high-efficiency planar solar cells, they have high surface-recombination velocities and, thus, are not ideal materials for nanostructured PV cells.
Researchers have developed a promising solar-cell module based on vertically oriented and spatially ordered cadmium sulfide (CdS) nanowires, or nanopillars (NPLs), embedded in a cadmium telluride (CdTe) thin film.
The CdS/CdTe combination has relatively low surface-recombination velocity and so is ideal for taking advantage of the high surface/junction area to promote carrier-collection efficiency. Significantly, they also achieved template-assisted growth of highly or- dered NPL arrays on aluminum foil, avoiding costly epitaxial growth.
The advantages of using NPL arrays for solar-energy collection are both optical and electrical in nature. As light passes through a 3D solar-cell structure, such as our NPL array, scattering increases the effective path length, thus increasing the absorption for a given device thickness.
Further, the NPL structure presents a graded refractive index to the incident light relative to the abrupt interfaces of a planar cell, effectively suppressing reflection. Electrically, the NPL structure decouples the light-absorption and carrier-collection directions. Thus, cells with thickness well matched to the absorption coefficient and NPL pitch well matched to minority-carrier diffusion length can be engineered.
To leverage these advantages, we developed a process that allows for control of the geometric parameters of the NPL array, including NPL diameter, pitch, length, and shape. In so doing, we can optimize for solar efficiency.