Spectrum-splitting is a research area in the field of solar energy technology that focuses on utilizing multiple solar cells with different bandgap energies to improve the overall efficiency of solar energy conversion. By splitting the solar spectrum into different wavelength ranges, each solar cell can efficiently capture a specific portion of the solar spectrum, allowing for higher overall efficiency compared to traditional single-junction solar cells. Spectrum-splitting technology has the potential to increase the efficiency and reduce the cost of solar energy systems, making them more competitive with traditional fossil fuel sources.