A silicon photocell is a semiconductor device that converts light energy directly into electrical energy.
Silicon photocells work on the principle of the photovolt-effect. When light is irradiated in the pN junction region of silicon photocell, photogenerated electron hole pairs are excited in the semiconductor. Under the action of internal electric field, most of the carriers cannot pass through the barrier layer, while a few carriers can pass through the barrier layer. As a result, the photogenerated electrons in the p region enter the N region, and the photogenerated holes in the N region enter the p region, so that the photogenerated electrons in each region are separated from each other. The accumulation of photogenerated electrons in the N region makes the N region negatively charged, and the accumulation of photogenerated electrons in the p region makes the p region positively charged. The photoelectromotive force is generated between the p and N regions. When the silicon photocell is connected to the load, the photocurrent flows from the p region through the load to the NE, and the power output is obtained in the load.