摘要：SummaryManipulation by external pressure of the optical response of 2D Metal Halide Perovskites (MHPs) is a fascinating route to tune their properties and promote the emergence of novel features. We investigate here DA2PbI4and DA2GeI4(DA = decylammonium) perovskites in the pressure range up to ∼12 GPa by X-ray powder diffraction, absorption, and photoluminescence spectroscopy. Although the two systems share a similar structural evolution with pressure, the optical properties are rather different and influenced by Pb or Ge. DA2PbI4shows a progressive red shift from 2.28 eV (P = 0 GPa) to 1.64 eV at 11.5 GPa, with a narrow PL emission, whereas DA2GeI4, changes from a non-PL system at ambient pressure to a clear broadband emitter centered around 730 nm with an intensity maximum at about 3.7 GPa. These results unveil the role of the central atom on the nature of emission under pressure in 2D MHPs containing a long alkyl chain.Graphical abstractDisplay OmittedHighlights•Phase separation of 2D perovskites containing decylammonium as a function of pressure•Strong red-shift of DA2PbI4has a function of pressure from 2.28 to 1.64 eV•Emergence of broad emission in DA2GeI4by increasing pressureEngineering; Materials chemistry; Materials characterization; Materials physics
