Why is fluorescence more common than phosphorescence? Why does fluorescence have two spectra?

Fluorescence is more common than phosphorescence because fluorescence has higher luminous intensity and longer duration after excitation, and can emit different colors through different excitation wavelengths, which has better spectral response performance. Fluorescence has two spectra because when the fluorescent substance is excited, electrons will jump from the ground state to the excited state and absorb energy, and then electrons will jump back from the excited state to the ground state and release energy, which is fluorescence. According to relevant published materials, the preparation and use of fluorescent materials are more convenient and flexible, and can be applied to various fields and application scenarios, such as biomedicine, material science, environmental monitoring and so on. Fluorescence is more common than phosphorescence and has become an important research and application direction in many fields. Fluorescence spectrum can be divided into excitation spectrum and emission spectrum. Excitation spectrum refers to the spectrum of light absorbed by the fluorescent substance before excitation, and emission spectrum refers to the spectrum of fluorescence emitted by the fluorescent substance after excitation. The difference between these two spectra is due to the different energy released by fluorescent substances when they transition from excited state to ground state, resulting in different wavelengths and intensities of optical signals.