Carrier dynamics in polycrystalline Bi2Se3 topological insulator thin films were investigated by femtosecond transient absorption spectroscopy (FTAS) at 77 K, by using an infrared pump photon of 0.62 eV energy and a white supercontinuum probe ranging from the near infrared to ultraviolet regions (0.9–3.5 eV). The Bi2Se3 samples were grown by vapor solid deposition, a quick, inexpensive, and easy-to-control growth technique to obtain films of different thicknesses, endowed with topological properties. FTAS spectra present several absorption bleaching signals, which can be attributed to electronic transitions involving both bulk and surface states present in the complex Bi2Se3 band structure. We observe clear differences in the rise times of several bleaching signals, differences that can be attributed to different band filling dynamics. Fast rise times are observed for transitions only involving bulk states, while a …