808 nm-excited multiband NIR emission with looping mechanism and intrinsic bistability in Er3+ singly-doped BiOCl layered semiconductor

Abstract In this work, under excitation at 808 nm, not only an unusual dominant emission of 2I11/2 → 4I15/2 transition (1.0 μm) but also the relatively weaker 1.55 μm luminesce (2I13/2 → 4I15/2) of Er3+ ions are observed with multi-phonon process and optical bistability behavior simultaneously for the first time. The bistability loops exhibit uniformly clockwise cycle characterized by a relatively lower trace of emission intensity at decreasing pump power. The result show that the looping behavior of NIR emissions has been found to be related to the 808 nm excited multi-photon band transition of BiOCl. Temperature sensing behavior of Er3+ indicate that such bistability effect is associated with thermally enhanced nonradiative decay and reduced luminescence quantum yield due to the strong pump-induced local thermal loading. This work may offer a novel insight into the transition behavior of lanthanides in layered semiconductors and promote the potential applications in optical switchers and temperature sensing.