Ultrafast and Nonlinear Optical Properties of Two-Dimensional Mo-Doped Dual Phase Inorganic Lead Halide Perovskite

Two-dimensional (2D) inorganic halide nanomaterials are finding tremendous attention owing to ease of synthesis, solution processability, superior electronic, optical, and mechanical properties resulting in versatile applications. All inorganic dual phase perovskite composites can have superior optoelectronic properties than a single phase one. In addition to dual phase, doping with various ions may open up new avenues for emerging applications of such materials. In this work, we report on the synthesis of colloidal 2D Mo-doped all inorganic dual phase mix halide perovskite (CsPbBr3/CsPb2Br5). The charge carrier dynamics in these nanostructures has been studied with femtosecond transient absorption technique. Our studies reveal that at low pump fluences cold carrier trapping predominantly affects relaxation dynamics at early time. However, Auger recombination of excitons dominates the early time carrier relaxation at high fluences. Additionally, femtosecond Z-scan studies have been performed to elucidate the effect of photoinduced charge carriers on two photon absorption (TPA) properties of Mo-doped 2D perovskite. Our results could be useful for designing new low-dimensional perovskites for future linear and nonlinear optoelectronic applications.