The solar cell is a semiconductor device with photoelectric conversion characteristics. It directly converts solar radiation energy into direct current and is the most basic unit for photovoltaic energy production. The unique electrical properties of solar cells are achieved by doping certain elements (such as phosphorus or boron) into crystalline silicon. This creates a permanent imbalance in the molecular charge of the material, forming a semiconductor material with particular electrical properties. Under sunlight, free charges can be generated in semiconductors with special electrical properties. These free charges move in one direction and accumulate, forming an electromotive force at both ends. When both ends are closed by a conductor, a current is generated. This phenomenon is called photovoltaic effect, or photovo effect.ltaic for short.
The most widely used monocrystalline silicon solar cell at present is composed of two layers of semiconductor materials with a thickness of about 0.25 mm, forming two zones: one zone of positive charge and a zone of negative charge. The negative zone is located in the upper layer of the battery. In this layer, elements such as phosphorus and boron are forced to penetrate and stick to the silicon. The positive area is placed below the surface of the battery and the positive and negative interface areas are called P-N junctions. The P-N junction has constant physical properties during battery manufacturing. When sunlight hits the electrons that remain free in the battery, these electrons near the P-N junction move towards the surface of the battery. When a metal wire is used to connect the positive voltage level of the solar cell to the loadin volts, a metal wire is used to connect the positive voltage level of the solar cell to the voltage load. current is formed in the external circuit. The electromotive force at the P-N junction of each basic unit of solar cell is about 0.5 V, and this voltage value has nothing to do with the size of the cell. The output current of a solar cell is affected by its surface area and the intensity of sunlight. A cell with a larger surface area can produce a stronger current.