The solar cells that can be seen everywhere today were originally tailor-made as "energy keys" for space exploration. In 1954, scientists at Bell Laboratories in the United States first developed silicon-based solar cells. Although the conversion efficiency was only 6% at the time, it laid the groundwork for solving the satellite energy problem - early artificial satellites relied on disposable chemical batteries with a range of only a few weeks, while the constant strong sunlight in space made solar energy an ideal energy source.

This' space exclusive 'technology gave back to Earth after the oil crisis in the 1970s, and as costs decreased, it entered millions of households from aerospace grade applications, becoming the core clean energy for addressing the climate crisis. The story of solar cells, from the "energy wings" of satellites to the "sunshine savings account" of Earth, is a romantic interweaving of human exploration of the universe and protection of our homeland.