Robust, Cationic Lead Halide Layered Materials with Efficient Broadband White-Light Emission

Abstract

Only a selected class of corrugated 2D hybrid lead halide perovskites exhibit broadband white-light emission from self-trapped excitons. Recently, we have discovered ultrastable layered lead halide photoemitters overcoming the stability problems of perovskites, despite in need of deep-UV irradiation to achieve photoluminescence quantum efficiency (PLQE) of over 10%. Herein, we have employed a robust, nonconjugated dicarboxylate ligand to pillar the cationic 1D [PbBr]+ chains. The unique corrugated stacking of [PbBr]+ chains facilitates the structural deformation to form self-trapped excitons, thus enabling an eightfold enhancement of PLQE over our previous reported bilayer bromoplumbate structures. The PLQE of 17.2% is not only among the highest in all of the layered lead halide white-light emitters, but overcoming the problem of our previous photoemitters requires deep-UV LED excitation. In addition, by tuning the stacking mode of the pillaring molecules, the chloride analog successfully incorporates a s...