Bulk assemblies of zero-dimensional (0D) metal halides with exceptional structural versatility have enabled the development of a number of highly efficient emitters with tunable photophysical properties. Here, we report a novel single crystalline bulk assembly of multicomponent 0D metal halides, (bmpy) 9 [SbCl 5 ] 2 [Pb 3 Cl 11 ] (bmpy = 1-butyl-1-methylpyrrolidinium), which exhibits dual emissions from distinct metal halide species. Excitation-dependent warm white light emissions with high photoluminescence quantum efficiencies of >70% can be obtained by combining green emission from Pb 3 Cl 11 5− and orange emission from SbCl 5 2− . Because of complete site isolation by wide bandgap organic moieties and little-to-no spectral overlaps, no energy transfer occurs between two distinct emitting species, allowing for precise color control by manipulating the excitation wavelengths. Our discovery of dual emitting organic metal halide hybrid opens up a new way to develop precisely ordered single-crystalline multicomponent materials with multi-functionalities.

Single crystalline bulk assemblies of metal halide clusters show great potential as highly efficient light emitters with tunable photophysical properties. However, synthetic control of the geometry of the clusters in a rational manner has not been well established, and the relationships between the photophysical properties and structures of this emerging class of zero-dimensional materials are still not well understood. Here, we report the synthesis and characterization of two bulk assemblies of lead bromide clusters, (bmpy)6[Pb3Br12] (T1) and (bmpy)9[ZnBr4]2[Pb3Br11] (T2) (bmpy: 1-butyl-1-methylpyrrolidinium), which contain metal halide trimer clusters with different geometries. T1 with chain-shaped [Pb3Br12]6– clusters is not emissive at room temperature, whereas T2 with triangle-shaped [Pb3Br11]5– clusters exhibits yellowish-green emission peaked at 564 nm with a photoluminescence quantum efficiency of 7% at room temperature. Detailed analysis of the structural and photophysical properties show that the photophysical properties and excited-state dynamics of these materials are highly dependent on the geometry of the metal halide clusters.

Metal ion linked multilayers are a unique motif to spatially control and geometrically restrict molecules on a metal oxide surface, which is of interest in a number of promising applications. Here we use a bilayer composed of a metal oxide surface, an anthracene annihilator molecule, Zn(II) linking ion, and porphyrin sensitizers to probe the influence of the position of the metal ion binding site on energy transfer, photon upconversion, and photocurrent generation. Despite being energetically similar, varying the position of the carboxy metal ion binding group (i.e., ortho, meta, para) of the Pt(II) tetraphenyl porphyrin sensitizer had a large impact on energy transfer rates and upconverted photocurrent that can be attributed to differences in their geometries. From polarized attenuated total reflectance measurements of the bilayers on ITO, we found that the orientation of the first layer (anthracene) was largely unperturbed by subsequent layers. However, the tilt angle of the porphyrin plane varies dramatically from 41°to 64°to 57°for the p-, m-, and o-COOH substituted porphyrin molecules, which is likely responsible for the variation in energy transfer rates. We go on to show using molecular dynamics simulations that there is considerable flexibility in porphyrin orientation, indicating that an average structure is insufficient to predict the ensemble behavior. Instead, even a small subset of the population with highly favorable energy transfer rates can be the primary driver in increasing the likelihood of energy transfer. Gaining control of the orientation and its distribution will be a critical step in maximizing the potential of the metal ion linked structures.

Carbon monoxide (CO) is a gasotransmitter produced in humans. An essential unanswered question in the design of carbon monoxide releasing molecules (CORMs) is whether the delivery molecule should be localized extra- or intracellularly to produce desired biological effects. Herein we show that extracellular CO release is less toxic and is sufficient to produce an anti-inflammatory effect similar to that of intracellular CO release at nanomolar concentrations. This information is valuable for the design of CORMs.

Integrating molecular photon upconversion via triplet-triplet annihilation (TTA-UC) driectly into a solar cell offers a means of harnessing sub-bandgap, near infrared (NIR) photons and surpassing the Shockley-Quessier limit. However, all...