Photovoltaic modules, commonly known as solar panels, are devices that convert sunlight directly into electricity. This process is based on the photovoltaic effect, discovered in 1839. When sunlight hits the semiconductor material in solar cells, it generates an electric current that can power our homes and devices.
The first step in photovoltaic conversion is photon absorption. When a photon from sunlight strikes a silicon atom with energy greater than the band gap, it transfers its energy to an electron. This excites the electron, giving it enough energy to break free from its atomic bond. This process creates an electron-hole pair: a free electron and a positively charged hole where the electron used to be.
光伏组件是太阳能发电系统的核心部件。它通过光伏效应将太阳光能直接转换为电能。当阳光照射到光伏组件表面时，太阳能电池内部的半导体材料会产生电流，从而实现发电。这一技术为我们提供了清洁、可再生的能源解决方案。
光伏效应的第一步是光子激发。当太阳光中的光子撞击硅原子时，如果光子能量足够大，就能激发价带中的电子，使其跃迁到导带，同时在价带中留下一个空穴。这个过程形成了电子-空穴对，为后续的电流产生奠定了基础。
太阳能电池含有P-N结，这是P型和N型半导体材料之间的边界。P型区域有过量的空穴，而N型区域有过量的电子。这在结处形成了内建电场。当光子吸收产生电子-空穴对时，这个电场就像单向通道，将电子推向N型侧，将空穴推向P型侧，防止它们复合。
分离的电子和空穴形成电势差，当连接外部电路时，电子通过外部回路从N型区流向P型区，形成电流。太阳能电池的前表面有栅格状金属电极用于收集电流，后表面有全覆盖电极。这样的设计既能收集电流，又能让阳光尽可能多地进入电池内部。
光伏组件的发电效率受多种因素影响。太阳辐射强度直接影响发电量，正午时分效率最高。温度升高会降低电池效率，这就是为什么炎热天气下发电量可能不如预期。此外，太阳光的入射角度、电池材料特性、以及表面清洁度都会影响最终的发电效果。现代单晶硅电池板效率可达20%以上。
The separated charges create a voltage difference across the solar cell. When an external circuit is connected, electrons flow from the n-type region through the external circuit to the p-type region, generating electric current. Metal contacts on the front and back surfaces collect these charges. The front contact uses a grid pattern to maximize light entry while collecting current efficiently.
Solar panel efficiency is affected by several key factors. Solar irradiance intensity directly impacts power output, with peak efficiency occurring during midday. Temperature has a negative effect - higher temperatures reduce efficiency, which is why hot climates may not always produce the highest output. The angle of sunlight incidence, material quality, and surface cleanliness also play crucial roles. Modern silicon panels achieve efficiencies of over 20% under optimal conditions.