Dibenzo[a,e]pentalene derivatives as nonalternant conjugated hydrocarbons are attractive for use as ambipolar or n-type semiconductors in field-effect transistors. For organic semiconductors, not only the energy levels of the frontier molecular orbitals but also their solid-state packing is crucial for good charge transport abilities. The introduction of fluorine atoms into organic semiconductors can lead to a closer packing in the solid state, enabled through FMIDLINE HORIZONTAL ELLIPSISF, FMIDLINE HORIZONTAL ELLIPSISH, and FMIDLINE HORIZONTAL ELLIPSIS pi-interactions. We herein introduce pentafluorophenyl substituents into thioether- and sulfone-DBPs and demonstrate how these substituents not only further lower their LUMO energies to values down to -3.6 eV for the thioethers and -4.1 eV for the sulfone but also lead to a denser packing in the solid state due to fluorine-based interactions between the molecules.

Charge-transfer emitters are attractive due to their color tunability and potentially high photoluminescence quantum yields (PLQYs). We herein present tetraaminospirenes as donor moieties, which, in combination with a variety of acceptors, furnished 12 charge-transfer emitters with a range of emission colors and PLQYs of up to 99 %. The spatial separation of their frontier molecular orbitals was obtained through careful structural design, and two DA structures were confirmed by X-ray crystallography. A range of photophysical measurements supported by DFT calculations shed light on the optoelectronic properties of this new family of spiro-NN-donor-acceptor dyes.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

AbstractA new family of emissive donor–acceptor–donor (D-A-D) compounds has been developed by introducing two electron donors into the 7,8-diaza[5]helicene core as a novel helical electron acceptor. The X-ray crystallographic analyses revealed the uniquely twisted and helical structures of these compounds in the solid states. Notably, some D-A-D compounds developed herein display distinct mechanochromic luminescence (MCL) in the solid state, and a D-A-D helicene shows circularly polarized luminescence (CPL) with a relatively high luminescence dissymmetry factor g lum of ca. 10–3. Time-resolved spectroscopic analysis revealed the aspects of thermally activated delayed fluorescence characters of the helicenes. Furthermore, the emissive helicenes were applied to organic light-emitting diodes as emitters.

Spiroconjugated charge-transfer dyes with N–CO-substructure are presented, whose optical properties are tuned by extending the donor or acceptor part.

Ambipolar organic semiconductors are of high interest for organic field-effect transistors. For n-type conduction, low LUMO energies are required. Dibenzo[a,e]pentalenes (DBPs) are promising compounds; however, few derivatives exist with energetically low-lying LUMO levels. Here, we present DBP derivatives with LUMO energies down to -3.73 eV and small bandgaps down to 1.63 eV determined through cyclic voltammetry, UV/vis absorption spectroscopy, and TDDFT calculations. Single-crystal X-ray diffraction analysis revealed a 1D π-stacking mode. The addition of arylalkynyl substituents at the five-membered rings in a facile and versatile synthetic route allowed for tuning of the band gaps and LUMO energies. The synthetic route can easily be modified to access a variety of DBP derivatives. The LUMO energies of the DBP derivatives presented herein make them attractive for an application in n-type or ambipolar field-effect transistors.

Dibenzo[a,e]pentalenes, functionalized with thioether or sulfone groups, show high electron mobilities in n-channel OFETs using well-aligned crystals.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.