Control of π−π Interactions in Epitaxial Films of Platinum(II) Octaethyl Porphyrin

Abstract

Epitaxial thin films of Pt(II) octaethyl porphyrin were grown on the cleavage surface of graphite and potassium hydrogen phthalate. The structure of the films was characterized by high resolution atomic force microscopy, showing that the two substrates template the growth of two layered phases with dramatic structural differences, strongly influencing π-stacking of adjacent molecules. The impact of these characteristics on the electronic structure of the film phases is illustrated by a thorough optical investigation.

Kinetically controlled crystal growth approach to enhance triplet energy migration-based photon upconversion

“…A THF solution of PtOEP ð½PtOEP ¼ 10 μM) showed a Qð0;0Þ band at 534 nm, whereas this band is red-shifted to 552 nm in the cast solid sample due to aggregation. 41 Interestingly, absorption spectra obtained for PtOEP in DPA-PtOEP composite crystals showed blue shifts compared to that of the neat cast solid. Notably, the peaks of the condition 2A (537 nm) and 2B (536 nm) samples are more blue shifted compared to that of the crystals obtained under condition 1 (541 nm).…”

“…These results suggest that the triplet energy of the donor molecules is efficiently transferred to the surrounding acceptor molecules or thermally dissipated in the donor aggregates. 41 TTA-UC quantum yields for samples obtained under each condition were determined by the absolute method using the integrating sphere and the laser excitation source, to avoid inaccuracy that could arise from the strong light scattering of the crystals. In general, the quantum yield is defined as the ratio of absorbed photons to emitted photons, and thus the maximum yield (Φ UC ) of the bimolecular TTA-UC process is 50%.…”

Effect of substituent position on electrodeposition, morphology, and capacitance performance of polyindole bearing a carboxylic group

“…The 5,6,7-position belongs to para, meta and ortho with respect to the pyrrolic nitrogen atom, respectively, which leads to the steric effect increasing. It is well-known that less steric hindrance is more beneficial to form p-p stacking, and the p-p stacking may develop either along an in-plane direction, or along an out-of-plane one in the process of the film growth [79]. Therefore, the diameter sizes of 5-PICA and 6-PICA nanowires are larger than that of 7-PICA.…”

Growth of pseudomorphic structures through organic epitaxy

“…Line-online is found to be the most common lattice registry observed in the epitaxy of organic semiconductors. 17,19,35,36 This occurs because in molecular crystals surfaces are relatively more corrugated with respect to atomic materials, and corrugations run often along nonprimitive crystallographic directions, as in the paradigmatic case of PET(001) (Figure 1(b)). A minimum interface energy condition between two surfaces of molecular materials is then achieved by matching their directions of main corrugation.…”