Organic-Inorganic Layered and Hollow Tin Bromide Perovskite with Tunable Broadband Emission

Recently, layered perovskites attracted great attention for its excellent stability and light-emitting property. However, most of them rely on the toxic element lead and their emission quantum yields are generally low. Here, a unique hollow two-dimensional perovskite was developed in which the organic hexamethylene diamines (C₆H₁₈N₂²⁺) strongly coupled with distorted tin bromide anions (SnBr₆^4-). This toxic-free low-dimensional tin perovskite exhibits a broadband emission in the visible region with a high luminescence quantum yield of 86%. First-principles calculation indicate the broadband emission is associated with the recombination of self-trapped excitons. And the emission is related to the geometry of tin bromide anions. An ultraviolet light-pumped white light emitting diode with excellent color-rendering index of 94 was fabricated using it together with a commercially available blue phosphor.