What is the difference between indoor light source and sunlight, and can indoor light drive solar equipment?
answer:
The difference between indoor light sources and sunlight is mainly due to the different spectral distributions. We know that light is actually an electromagnetic wave, and electromagnetic waves can have different wavelengths; for different lights, the "content" of electromagnetic waves of different wavelengths in their composition is different, and through the method of spectral analysis, the "content" of electromagnetic waves of different wavelengths can be obtained, which is expressed by the intensity of light (that is, energy). The figure below shows the spectra of daylight and several common indoor light sources, and we can clearly see that their spectral composition is very different.
As for whether indoor light can drive solar equipment, to answer this question, we first need to explain the working principle of "solar equipment". General solar equipment refers to silicon photocells, and the working principle of silicon photocells is the so-called "photogenerated volt effect": when light shines on silicon photocells, the energy of light is absorbed by the battery (strictly speaking, the photon energy is absorbed by the silicon lattice), so that the positive and negative charges (electrons are excited to jump to form free electrons, leaving positively charged holes) separate and accumulate at both ends of the battery, and an electric field is generated inside the battery, thus forming an electric potential difference. If the two ends of the battery are connected with wires, then due to the existence of potential difference, there will be a current flowing through the wire (the current in this case is called short-circuit current). In order for the energy of photons to be absorbed, the wavelength of light needs to meet certain conditions, and for silicon photocells, the wavelength needs to be in the range of 400 to 1100 nm to be effectively absorbed. Combined with the above figure, we found that both sunlight and indoor light meet this condition, so indoor light can also drive solar equipment. It is worth noting that the ratio of light energy absorbed by batteries into electrical energy is not the same for different wavelengths of light. At the same light intensity, the size of the short-circuit current () corresponding to different wavelengths λ is shown in the following figure:
bibliography:
[1] Wang Dianyuan, Wang Qingkai, Peng Dan, Wu Xinghua, Zeng Wei, Guo Yanyan, Wang Youwen. Experimental Experiment on determination of spectral response curve of silicon solar cells[J].Physical Experiments,2007(09):8-10.
Song Aiqin. Study on the characteristics of silicon photocells[J].Laboratory Science,2011,14(02):102-104.
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