Organic metal halide hybrids with zero-dimensional (0D) structure at the molecular level, or single-crystalline bulk assemblies of metal halides, are an emerging class of light-emitting materials with high photoluminescence quantum efficiencies (PLQEs) and color tunability. Here we report the synthesis and characterization of a new single-crystalline bulk assembly of metal halide clusters, (bmpy) 9 [ZnCl 4 ] 2 [Pb 3 Cl 11 ] (bmpy: 1-butyl-1-methylpyrrolidinium), which exhibits green emission peaked at 512 nm with a remarkable near-unity PLQE at room temperature. Detailed structural and photophysical studies suggest that there are two emitting states in [Pb 3 Cl 11 ] 5− clusters, whose populations are strongly dependent on the surrounding molecular environment that controls the excitedstate structural distortion of [Pb 3 Cl 11 ] 5− clusters. High chemical-and photostability have also been demonstrated in this new material.

A series of 11 complexes of the type trans-(NHC) 2 Pt(CC-Ar) 2 (where NHC = N-heterocyclic carbene) have been synthesized and their photophysics characterized. The complexes display moderately efficient deep blue to green phosphorescence from a triplet excited state that is localized mainly in the aryl acetylide ligand (CC-Ar). The emission energy varies with the substituent on CC-Ar, with the highest energy emission for Ar = 4-pyridyl. The emission quantum efficiency and lifetime for the series decreases with increasing emission energy (E em ), and the effect is identified as arising from an increase in the nonradiative decay rate (k nr ) with E em . Temperature-dependent emission lifetime studies for three complexes give activation energies for the nonradiative decay process ∼1000 cm −1 , and the thermally activated decay process is attributed to crossing to a nonemissive metal-centered (d−d) excited state. At a low temperature, two different emission progressions are observed. Density functional theory calculations suggest that the triplet energy varies with the torsion of the aryl acetylide rings relative to the plane defined by the PtC 4 unit (where C = the carbon atoms bonded to Pt). The multiple emission is ascribed to emission from complexes differing with respect to the aryl acetylide ring torsion. Ultrafast transient absorption spectroscopy reveals a fast relaxation (∼5 ps) that may also be due to aryl acetylide ring torsional relaxation in the triplet excited state.

A single crystalline organic metal halide hybrid containing arrays of one-dimensional metal halide nanotubes is discovered for the first time.