Solar panels are an efficient device that responds to light and can convert light energy into electricity. There are many kinds of materials that can produce photovoltaic effect, such as monocrystalline silicon, polysilicon, amorphous silicon, gallium arsenide, indium copper selenide, etc., the power generation principle of various materials is basically the same, here, take crystalline silicon as an example, describe the principle process of solar panels. P-type crystalline silicon is doped with phosphorus to obtain N-type silicon and form P-N junction.

When light hits the basic surface of the solar panel, some of the photons are absorbed by the silicon material; The energy of the photon is transferred to the silicon atom, so that the electrons become free electrons, and the potential difference is gathered on both sides of the P-N junction. When the circuit is externally connected, under the action of this voltage, there will be current flowing through the external circuit, thus producing a certain output power. The essence of this process is the conversion of photon energy into electrical energy.

Solar panels are an important means of human use of solar energy, its power generation usually has two ways, one is light-heat-electricity conversion mode, the other is light-electricity direct conversion mode. Let's take a look at these two ways of generating electricity.

1, light-heat-electricity conversion method: is the use of solar radiation generated by the heat of a process of power generation, it is generally by the solar collector will absorb the heat into the working medium steam, and then drive the turbine power generation. The former process is the light-heat conversion process, and the latter process is the heat-electricity conversion process, which is the same as the ordinary thermal power generation.

2, light-electricity direct conversion mode: the use of photoelectric effect to directly convert solar radiation into electricity, the basic device is solar panels. Solar panels are the use of photovoltaic effect and the direct conversion of solar energy into electrical energy equipment, belongs to the semiconductor photodiode, when the sun shines on the photodiode, the photodiode will turn the solar light into electrical energy, resulting in current. When multiple solar panels are connected in series or in parallel, it can become a solar cell array with a larger output power.

Solar panel thermal power generation has the disadvantages of low efficiency and high cost, and it is estimated that the investment is at least 5 to 10 times more expensive than ordinary thermal power stations. A 1000MW solar thermal power station requires an investment of 2 to 2.5 billion US dollars, and the average 1kW investment is 2000 to 2500 US dollars. Therefore, solar panels are only suitable for small-scale special occasions, and large-scale use is extremely uneconomical from the current point of view, so it can not compete with ordinary thermal or nuclear power plants.

Although solar energy is a very environmentally friendly energy, solar cells are also a good way to save energy, but in terms of current technology, the production cost of solar cells is still relatively high, so it has not been popularized. However, the application of clean energy will be an inevitable trend, and solar energy is almost pollution-free, whether from an energy perspective or from the perspective of environmental protection, the development of solar energy will be a matter that needs to be vigorously developed in the future. Perhaps in the near future, we will have solar cells in our homes.