Temperature-Dependent Photoluminescence of Zero-Dimensional Hybrid Bimetallic Chloride [Mn(DMSO)₆][SbCl₅]

Hybrid metal halides are a novel class of optoelectronic materials characterized by exceptional light absorption capability, high photoconversion efficiency, elevated photoluminescence quantum yield (PLQY), tunable band gap, and stable optical property. These hybrid metal halides are considered as promising candidates for various applications, including light-emitting diodes, optical sensors, nonlinear optical materials, and photovoltaic devices. In this study, we prepare samples using a solvent evaporation method, in which the solvent dimethyl sulfoxide (DMSO) is used to synthesize the zero-dimensional hybrid bimetallic complex [Mn(DMSO)<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf>] [SbCl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf>]. Steady-state photoluminescence (PL) spectroscopy reveals that it exhibits broadband emission in the red-orange region, which is attributed to the recombination of triplet states of Sb<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>and the characteristic emission from Mn<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>metal. This finding confirms the presence of singlet photon absorption in [Mn(DMSO)<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf>] [SbCl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf>]. The PL excitation spectra are employed to investigate the two luminescent centers of [Mn(DMSO)<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf>][SbCl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf>], which correspond to the singlet state of Sb<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>+ and the interplay between the triplet state of Sb<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>+ and the luminescence of Mn2<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>. Temperature-dependent steady-state and time-resolved PL spectroscopy show that with increasing temperature, the PL intensity decreased, the emission peak underwent a redshift, and the PL lifetime shortened, indicating that the non-radiative recombination process enhanced by electron-phonon coupling is intensified at elevated temperatures. Peak fitting analysis yields the exciton binding energy, with a relatively high exciton binding energy favoring the promotion of radiative recombination. These findings provide significant insights into the potential applications of zero-dimensional hybrid bimetallic chlorides in optical sensors and light-emitting diodes.