H/F Substitution-Engineered Argentophilic Interactions for Enhanced Photoluminescence in 1D Hybrid Silver Halides

Abstract

Organic-inorganic hybrid silver halides have emerged as promising materials for optoelectronic devices due to their unique photoluminescence (PL) properties, excellent stability, and environmental benignity. However, their PL efficiency remains limited by weak Ag⁺-centered radiative recombination and significant non-radiative losses. Herein, we report on a facile hydrogen-to-fluorine (H/F) substitution strategy to enhance luminescent performance in hybrid silver halides by strengthening argentophilic interactions. Using tetraethylammonium (TEA⁺) and its fluorinated analogue triethyl(2-fluoroethyl)ammonium (FTEA⁺), we synthesized two isostructural one-dimensional silver bromide hybrids: (TEA)Ag₂Br₃ and (FTEA)Ag₂Br₃. The fluorinated compound exhibits a broadband yellow-white emission with a PL quantum yield (PLQY) of 11.9%, markedly higher than the <1% PLQY of weak blue light emission for its non-fluorinated counterpart. Density functional theory calculations reveal that enhanced metal-to-metal charge transfer (MMCT) and halide-to-metal charge transfer (XMCT) processes, promoted by reduced Ag···Ag distances via F···Br interactions, are responsible for the improved PL properties. This substitution strategy was further validated in silver iodide systems, confirming its general applicability. Moreover, the excellent thermal stability and broad emission profile of (FTEA)Ag₂Br₃ enable its integration into white light-emitting diodes, achieving a high color rendering index of 82.7. These observations provide a new avenue for rational design of high-performance Ag-based hybrid luminescent materials.

Keywords

Organic-inorganic hybrid composites / Silver halides / Photoluminescence / Argentophilic interaction / Hydrogen-to-fluorine substitution / Charge transfer / Light-emitting devices / Hydrothermal synthesis

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