In previous issues, we introduced flexible solar cells among thin film solar cells, which have advanced technology, excellent performance, low cost, and wide range of uses. Its application is also different from traditional solar cells, adding more possibilities to the photovoltaic industry. Millennial Solar will introduce you to the various classifications of this type of solar cell.

(Silicon) crystalline flexible solar panels

These are the most commonly used on the market and are made from the same silicon material that traditional panels are made from. Here, a solar "panel" is made up of many crystalline, photovoltaic flexible solar cells.

If the underlying material is silicon, why are traditional panels flat and bulky, while flexible solar panels are thin and light? This is because they stack up differently. For lightweight solar panels, for example, silicon wafers are cut a few micrometers (μm) thick, giving them the illusion of flexibility because they can bend up to 30 degrees.

In fact, this 30 degrees of flexibility is enough to allow it to be easily installed on curved surfaces, including boats. They are also often used as flexible solar panels for motorhomes (also known as caravan solar panels). In comparison, wafers in traditional solar panels are cut to about 200μm thick, making them thicker and heavier.

Next, thin layers of flexible silicon panels are placed between protective layers (usually made of plastic) to extend durability and portability. (Compare that to the thick layers of glass used in rooftop solar panels. As you can imagine, these lightweight solar panels can produce a limited amount of solar energy, so there are 50-watt, 100-watt, 200-watt, and 300-watt varieties.

However, they have a reasonable efficiency (15%-25%) in converting light into energy and thus can serve as energy reservoirs.

Thin film flexible solar panels

This is a relatively emerging technology in which photovoltaic materials are printed or pasted onto thin surfaces (including cloth, thick paper, aluminum sheets, etc.). Without the protection of silicon, they are considered far less durable than their crystalline counterparts. However, this is still an evolving technology.

The main advantage of using thin portable solar panels is their extreme flexibility. They can be rolled up for storage, so they're perfect for camping trips where you probably won't care if they last a few years. This also makes them very lightweight, with some products weighing just 1.8kg.

Flexible panels made from organic cells/materials

Research currently underway at MIT is focused on producing strong, flexible solar panels made primarily from organic materials. The main challenge so far has been the brittleness of the electrodes. In a recent breakthrough, graphene electrodes were introduced. As a result, the solar industry has high hopes for the production of higher quality solar panels with enhanced flexibility and extended durability.

3D Confocal Microscope

3D Confocal Microscope ME-PT3000 is a high-speed confocal scanning microscope for accurate and reliable 3-dimensional (3D) measurements. Real-time confocal microscopy images are achieved through fast optical scanning modules and signal processing algorithms.

ME-PT3000 3D Confocal Microscope is an optical instrument specially used in the photovoltaic industry for quality inspection of grid lines and textured surfaces on the surface of photovoltaic cells. Based on the principle of optical technology, combined with precision Z-direction scanning module, 3D modeling algorithm, etc., the device surface is non-contactly scanned and a 3D surface image is established. The height and width of the grid lines on the photovoltaic cell and the textured surface are measured through the system software. The number of pyramids is quantitatively tested to provide feedback on the quality of photovoltaic cell cleaning, texturing and screen printing processes.

E-mail: market@millennialsolar.com

Compared with traditional cells, flexible solar cells may use roughly the same materials in mainstream products, but new companies and schools have been researching new materials, and solar cells have more application space.