Most conductive polymers only transmit electricity with dopants. Herein, we reported an undoped polymer PDAPI which was synthesized via a single-step reaction. Without any dopants, PDAPI powder revealed an intrinsically high conductivity of 4.1 ± 1 S/cm. Electrodes composed of PDAPI in lithium- and sodium-ion batteries (LIBs and SIBs) with reversible capacities of 498 and 310 mA h g–1, respectively. After 500 cycles there was no proven capacity degradation for PDAPI-based LIB and only 20% capacity loss in PDAPI-based SIB. These findings represented PDAPI advantages, including quinoid structure for high conductivity, free of doping for good reproducibility, and low solubility for ultrasustainability.
A series of near-infrared (NIR) organic absorbers, named FNs and FPs, have been obtained with absorption maxima from 870 nm to 1100 nm and thus falling into the attractive second near-infrared region (NIR-II). The synthesis of their extended aromatic cores utilized an initial arylamination between 4-aminonaphthalene-1,8-dicarboximide (NMI-NH 2 ) or 9-aminoperylene-3,4-dicarboximide (PMI-NH 2 ) with chloro-substituted 9,10-anthraquinones followed by a novel base-induced cyclodehydrogenation. A NIR-II pigment, compound FPP, was obtained through de-alkylation of a soluble precursor. The synthesis of this photostable pigment is high-yielding and avoids column chromatographic purification which is important for many applications.
A novel trimeric perylenediimide (PDI) macrocycle was synthesized, and its intramolecular electronic couplings were investigated by bulk and single-molecule optical spectroscopy and by various theoretical approaches. In polarization-resolved excitation spectroscopy at 1.2 K in a PMMA matrix, the appearance and disappearance of the three zero-phonon lines (ZPLs) of an individual trimer by changing the polarization in steps of 60° nicely reflect an approximate triangular geometry of the macrocycle and indicate localized excitations that are transferred by incoherent hopping processes at time scales of around 1 ps as inferred from the ZPL linewidths. The electronic coupling strength deduced from the low temperature data is found to be in good agreement with theoretical estimates. Bulk spectroscopy in toluene at room temperature indicates that the excitations are also localized under these conditions. Theory reveals that the reasons for the localized nature of the excitations at room and low temperatures are different. For a rigid macrocycle, the excitations are predicted to be delocalized, but molecular dynamics simulations point to considerable structural flexibility at ambient temperatures, which counteracts excitation delocalization. At 1.2 K in a PMMA matrix, this effect is too small to lead to localization. Yet, supported by simple model calculations, the disorder in the PMMA host induces sufficient differences between the PDI chromophores, which again result in localized excitations. By addressing crucial aspects of excitation energy transfer, our combined approach provides a detailed and quantitative account of the interchromophore communication in a trimeric macrocycle.
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