Buizza, Leonardo R. V.Wright, Adam D.Longo, GiuliaSansom, Harry C.Xia, Chelsea Q.Rosseinsky, Matthew J.Johnston, Michael B.Snaith, Henry J.Herz, Laura M.2026-02-262026-02-262021-05-14https://riunet.upv.es/handle/10251/232934[EN] Lead-free silver-bismuth semiconductors have become increasingly popular materials for optoelectronic applications, building upon the success of lead halide perovskites. In these materials, charge-lattice couplings fundamentally determine charge transport, critically affecting device performance. In this study, we investigate the optoelectronic properties of the recently discovered lead-free semiconductor Cu2AgBiI6 using temperature-dependent photoluminescence, absorption, and optical-pump terahertz-probe spectroscopy. We report ultrafast charge-carrier localization effects, evident from sharp THz photoconductivity decays occurring within a few picoseconds after excitation and a rise in intensity with decreasing temperature of long-lived, highly Stokes-shifted photoluminescence. We conclude that charge carriers in Cu2AgBiI6 are subject to strong charge-lattice coupling. However, such small polarons still exhibit mobilities in excess of 1 cm(2) V-1 s(-1) at room temperature because of low energetic barriers to formation and transport. Together with a low exciton binding energy of similar to 29 meV and a direct band gap near 2.1 eV, these findings highlight Cu2AgBiI6 as an attractive lead-free material for photovoltaic applications.Reconocimiento (by)Halide Double PerovskitesWhite-light emissionTemperature-DependenceLattice-RelaxationDynamicsElectronCS2AGBIBR6ExcitonRecombinationMotionArtículo10.1021/acsenergylett.1c00458Abierto2380-819534056108PMC8155390