Mechanism of Hot-Carrier Photoluminescence in Sn-Based Perovskites.

Metal halide perovskites have shown exceptionally slow hot-carrier cooling, which has been attributed to various physical mechanisms without reaching a consensus. Here, experiment and theory are combined to unveil the carrier cooling process in formamidinium (FA) and caesium (Cs) tin triiodide thin films. Through impulsive vibrational spectroscopy and molecular dynamics, much shorter phonon dephasing times of the hybrid perovskite, which accounts for the larger blueshift in the photoluminescence seen at high excitation density for FASnI compared to CsSnI is reported.

Cation Influence on Hot-Carrier Relaxation in Tin Triiodide Perovskite Thin Films.

Slow hot-carrier cooling may potentially allow overcoming the maximum achievable power conversion efficiency of single-junction solar cells. For formamidinium tin triiodide, an exceptional slow cooling time of a few nanoseconds was reported. However, a systematic study of the cation influence, as is present for lead compounds, is lacking.

The Origin of Broad Emission in ⟨100⟩ Two-Dimensional Perovskites: Extrinsic vs Intrinsic Processes.

2D metal halide perovskites can show narrow and broad emission bands (BEs), and the latter's origin is hotly debated. A widespread opinion assigns BEs to the recombination of intrinsic self-trapped excitons (STEs), whereas recent studies indicate they can have an extrinsic defect-related origin. Here, we carry out a combined experimental-computational study into the microscopic origin of BEs for a series of prototypical phenylethylammonium-based 2D perovskites, comprising different metals (Pb, Sn) and halides (I, Br, Cl).

Tin Halide Perovskites: From Fundamental Properties to Solar Cells.

Metal halide perovskites have unique optical and electrical properties, which make them an excellent class of materials for a broad spectrum of optoelectronic applications. However, it is with photovoltaic devices that this class of materials has reached the apotheosis of popularity. High power conversion efficiencies are achieved with lead-based compounds, which are toxic to the environment.