1、 In semiconductor materials, silicon element has become the most ideal photovoltaic material due to its unique electronic structure. The outermost layer of silicon atoms has four valence electrons, which can be doped with phosphorus or boron elements to form N-type or P-type semiconductors. When these two semiconductors are combined, a PN junction is formed at the interface, generating a built-in electric field.
Sunlight is an energy flow composed of photons of different wavelengths. Electronic transitions can only be excited when the photon energy is greater than the semiconductor bandgap. The bandgap width of silicon material is 1.12 electron volts, which perfectly matches the strongest energy region in the solar spectrum. This is the key reason why silicon has become a mainstream photovoltaic material
2、 Structure and Manufacturing of Photovoltaic Panels
A standard photovoltaic panel consists of multiple photovoltaic cells, each of which is an independent power generation unit. The surface of the battery is covered with an anti reflection film, with an N-type silicon layer below, a PN junction in the middle, and a P-type silicon layer at the bottom. These layered structures are manufactured through precision processes to ensure maximum photoelectric conversion efficiency
The manufacturing process of photovoltaic panels is extremely complex. From the purification of high-purity silicon, to the drawing of monocrystalline silicon rods, to the cutting, doping, and coating of silicon wafers, each step requires nanometer level precision control. Modern photovoltaic factories use automated production lines to complete these precision operations in a dust-free environment.
The performance of photovoltaic panels is mainly determined by conversion efficiency, temperature coefficient, and attenuation rate. At present, the conversion efficiency of commercial photovoltaic panels is between 18-22%, and the laboratory efficiency has exceeded 26%. For every 1 degree increase in temperature, the efficiency decreases by about 0.4%, so heat dissipation design is crucial.
3、 The Future Path of Photovoltaic Technology
The new generation of photovoltaic technology is breaking through the limitations of traditional silicon-based cells. Perovskite solar cells have become the most promising alternative due to their high efficiency and low cost advantages. Stacked cells can more fully utilize solar spectra by combining materials with different bandgaps.
Building Integrated Photovoltaics (BIPV) integrates photovoltaic modules directly into the exterior of buildings, providing both power generation and shading. Flexible photovoltaic materials can be made into curved or foldable forms, expanding their application scenarios. These innovations are reshaping the face of the photovoltaic industry.
Driven by the goal of carbon neutrality, the photovoltaic industry has entered a golden period of development. It is expected that by 2030, the global installed capacity of photovoltaics will reach 5000GW, and the annual power generation can meet 20% of the world's electricity demand. Photovoltaic technology is leading humanity towards a new era of clean energy.
From accidental discoveries in the laboratory to the world changing energy revolution, photovoltaic technology has come a long way. Every improvement in efficiency and breakthrough in technology embodies the wisdom of scientists and engineers. In places where the sun shines, photovoltaic panels are converting light energy into clean electricity, injecting sustainable development into human civilization. This is not only a technological advancement, but also a beautiful vision of harmonious coexistence between humans and nature.