RESUMEN
The photophysical tuning is reported for a series of tetraphenylphosphonium (TPP) metal halide hybrids containing distinct metal halides, TPP2 MXn (MXn =SbCl5 , MnCl4 , ZnCl4 , ZnCl2 Br2 , ZnBr4 ), from efficient phosphorescence to ultralong afterglow. The afterglow properties of TPP+ cations could be suspended for the hybrids containing low band gap emissive metal halide species, such as SbCl5 2- and MnCl4 2- , but significantly enhanced for the hybrids containing wide band gap non-emissive ZnCl4 2- . Structural and photophysical studies reveal that the enhanced afterglow is attributed to stronger π-π stacking and intermolecular electronic coupling between TPP+ cations in TPP2 ZnCl4 than in the pristine organic ionic compound TPPCl. Moreover, the afterglow in TPP2 ZnX4 can be tuned by controlling the halide composition, with the change from Cl to Br resulting in a shorter afterglow due to the heavy atom effect.
RESUMEN
Zero-dimensional (0D) organic metal halide hybrids, in which organic and metal halide ions cocrystallize to form neutral species, are a promising platform for the development of multifunctional crystalline materials. Herein we report the design, synthesis, and characterization of a ternary 0D organic metal halide hybrid, (HMTA)4 PbMn0.69 Sn0.31 Br8 , in which the organic cation N-benzylhexamethylenetetrammonium (HMTA+ , C13 H19 N4 + ) cocrystallizes with PbBr4 2- , MnBr4 2- , and SnBr4 2- . The wide band gap of the organic cation and distinct optical characteristics of the three metal bromide anions enabled the single-crystalline "host-guest" system to exhibit emissions from multiple "guest" metal halide species simultaneously. The combination of these emissions led to near-perfect white emission with a photoluminescence quantum efficiency of around 73 %. Owing to distinct excitations of the three metal halide species, warm- to cool-white emissions could be generated by controlling the excitation wavelength.