It is known that energy generation and storage are some of the problems of current society and the environment. Among the possible solutions proposed, solar energy is accepted as one of them. From semiconductor materials, electrical energy can be generated through the use of solar cells. Solar cells allow the absorption of photons from the sun, converting them into electrical energy. Among the abundant and non-contaminating semiconductor materials is silicon, with Si solar cells being the most marketed, offering an alternative for environmentally friendly electricity generation. There are other semiconductor materials that allow for better device efficiencies compared to Si, such as semiconductors formed by the III-V groups. Although these materials may have better performance, they are hindered by the need to be grown on substrates like Ge or GaAs, which are costly. In the 4SUNS project, we are developing III-V semiconductors on Si substrates to achieve high-efficiency solar cells at low cost. To grow III-V semiconductors on Si, we are using highly lattice-mismatched materials, which we have shown to have better utilization of the solar spectrum, able to absorb from 3 different spectral regions. Additionally, these materials have demonstrated new optoelectronic and electrical properties that are allowing us to develop a new device with the essence of a microchip, offering an opportunity for the fields of microelectronics and solar energy.