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.

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X-ray scintillators based on organic chromophores have the potential to deliver low-cost radiation detection products with fast response signals. However, their relatively low performance compared with that of widely used inorganic scintillators in terms of X-ray attenuation and light output has limited their applications. Here we report a dramatically improved scintillation performance for a BODIPY dye, difluoro(4via sensitization by a 0D organic metal halide, tetraphenylphosphonium manganese bromide ((C 24 H 20 P) 2 MnBr 4 ). By blending PM 570 and (C 24 H 20 P) 2 MnBr 4 in an appropriate ratio together in a polydimethylsiloxane matrix, we prepare plastic scintillators to exhibit a more than 15-fold increment of radioluminescence from PM 570. Such an enhancement is attributed to the excellent X-ray scintillation property of (C 24 H 20 P) 2 MnBr 4 and the efficient energy transfer from (C 24 H 20 P) 2 MnBr 4 to PM 570. These multicomponent plastic scintillators also exhibit an excellent linear response to the X-ray dose rate and a low detection limit of 22.5 nGy s −1 .

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