The basic principle of photovoltaic power generation
Photovoltaic power generation is based on the "photovoltaic effect." When photons from sunlight strike a material, they can transfer their energy to electrons within that material. If the energy is sufficient, the electron can break free from its atomic bonds and become a free electron, creating an electric current in the process. This process begins with the conversion of light into electricity. When light hits a semiconductor, it creates a potential difference between different regions of the material—such as between a metal and a semiconductor or between two types of semiconductors. This voltage acts like a dam, holding back the flow of electrons. Once a circuit is completed, the electrons can move freely, generating a continuous electric current. The core mechanism behind photovoltaic systems lies in the behavior of semiconductors. Silicon, for example, has four valence electrons. By introducing impurities like phosphorus (which has five electrons), we create an N-type semiconductor, which has extra electrons. Conversely, adding boron (with three electrons) creates a P-type semiconductor, which has fewer electrons, resulting in positive charge carriers known as holes. When N-type and P-type materials are joined, a PN junction is formed, which is the fundamental building block of a solar cell. When sunlight strikes the PN junction, it energizes the electrons, causing them to move across the junction. Electrons flow from the P-side to the N-side, while holes move in the opposite direction, creating a continuous flow of electric current. This is how solar panels convert sunlight directly into usable electricity. The manufacturing process starts with raw silicon, which is melted and solidified into ingots. These ingots are then sliced into thin wafers. Through doping and diffusion, a PN junction is created on each wafer. A grid of silver paste is screen-printed onto the surface to collect the generated current, and a back electrode is formed during sintering. An anti-reflective coating is also applied to increase efficiency by reducing light loss. These individual solar cells are then connected together in series or parallel to form a larger module. The entire assembly is usually encased in an aluminum frame, covered with tempered glass on the front, and mounted with a protective backsheet. Additional components such as inverters, batteries, and mounting structures are added to complete the system. Inverters are essential to convert the direct current (DC) produced by the panels into alternating current (AC), which can be used in homes or fed into the electrical grid. Costs associated with solar power systems are distributed across several areas. Solar panels themselves typically account for about 50% of the total cost, while inverters, installation, and other components make up the remaining half. Despite this, the long-term benefits of clean, renewable energy make photovoltaic systems a smart investment for both environmental and economic reasons. Heilongjiang Junhe Building Materials Technology Co., Ltd , https://www.junhejiancai.com