Glass-Type Solar Cells

Panasonic's glass-type solar cells come in a variety of shapes and voltages for outdoor and indoor applications. These applications include calculators, scales, landscape lighting, and outdoor markers. 

Solar-cell power is generated using the photovoltaic effect of semiconductors. When a semiconductor is exposed to a light source of suitable intensity, a large number of pairs consisting of an electron and a positive hole are generated as a result of the reciprocal action between photons and silicon atoms. At a p/n junction, between two different semiconductor materials, the electrons are diffused in the n-type material and the positive holes are scattered in the p-type material. They are then collected at both electrodes respectively, resulting in a voltage difference between the electrodes.

When an external load is connected, electricity flows through the load. In this way, an a-Si solar cell converts light energy into electricity and supplies power to external loads.

Since multiple cells can be connected in a series at the same time as the cells are formed, unlike the fabrication technique used with crystalline solar cells in which cells cut apart and then connected, it is easy to create batteries with a variety of voltages. This series connection idea is the same as that used with regular batteries.

The methods used to form amorphous films have special features that allow other substrates, such as stainless steel or plastic films, to be used in place of the usual glass substrate. This means that previously unknown solar cells, solar cells that are round, square, or any complex shape, or solar cells that can be bent, can be created. It is also possible to create areas in these solar cells that consist of just transparent glass by etching.

The human eye is sensitive to light with wavelengths from about 400 nm to 700 nm. Since amorphous, silicon solar cells are sensitive to light with essentially the same wavelengths, in addition to solar cells, they can also be used as visible light sensors.