Understanding the Effect of Sb Substitution on the Structural Distortion and Luminescence Properties in a Series of 0D Hybrid Metal Halides: (2-ABI)3Bi1−xSbxCl6.H2O

Abstract

Zero-dimensional (0D) organic-inorganic metal halides (OIMHs) have surfaced as an intriguing class of materials in the field of solid-state lighting owing to their outstanding self-trapped exciton (STE)-induced photoluminescence properties. In this work, we present two novel 0D Bi/Sb-based OIMHs, (2-ABI)3MCl6.H2O (M = Bi, Sb), which crystallize in the monoclinic P21/n space group. Under 365 nm UV light excitation, the Sb-analogue reveals a bright and broad yellow emission band at 580 nm, with a photoluminescence quantum yield (PLQY) of 34.6%. This can be ascribed to the distortion-induced STEs. Theoretical analysis of (2-ABI)3SbCl6.H2O in both ground and excited states indicates that certain bonds are significantly distorted, indicating the role of the stereoactivity of the 5s2 lone pair. To investigate the effect of gradual Sb substitution on the structure and optical properties of (2-ABI)3BiCl6.H2O, a series of mixed compounds, (2-ABI)3Bi1−xSbxCl6.H2O (refined x values = 0, 0.11, 0.40, 0.53, 0.87, 1), was synthesized. Additionally, a white light-emitting diode (WLED) based on the Sb compound was fabricated on a 390 nm UV LED, which displayed an impressive CRI value of 89.0 and CCT value of 6034 K, thereby demonstrating the potential of the titled Sb-compound towards cost-effective solid-state lighting applications.