Fullerene/Sulfur-Bridged Annulene Cocrystals: Two-Dimensional Segregated Heterojunctions with Ambipolar Transport Properties and Photoresponsivity

Fullerene/sulfur-bridged annulene cocrystals with a two-dimensional segregated alternating layer structure were prepared by a simple solution process. Single-crystal analysis revealed the existence of continuing π–π interactions in both the donor and acceptor layers, which serve as transport paths for holes and electrons separately. The ambipolar transport behaviors were demonstrated with single-crystal field-effect transistors and rationalized by quantum calculations. Meanwhile, preliminary photoresponsivity was observed with the transistor configuration

Fullerene/Sulfur-Bridged Annulene Cocrystals: Two-Dimensional Segregated Heterojunctions with Ambipolar Transport Properties and Photoresponsivity

Fullerene/sulfur-bridged annulene cocrystals with a two-dimensional segregated alternating layer structure were prepared by a simple solution process. Single-crystal analysis revealed the existence of continuing π–π interactions in both the donor and acceptor layers, which serve as transport paths for holes and electrons separately. The ambipolar transport behaviors were demonstrated with single-crystal field-effect transistors and rationalized by quantum calculations. Meanwhile, preliminary photoresponsivity was observed with the transistor configuration

Extended π‑Conjugated Molecules Derived from Naphthalene Diimides toward Organic Emissive and Semiconducting Materials

In this paper, a new synthetic way to modify naphthalene diimide (NDI) at “shoulder” positions is reported. The key step of the transformation is the intramolecular cyclization involving ethynyl and imidecarbonyl groups. The structure of the intermediate pyrylium cation was confirmed by X-ray crystal structural analysis. New conjugated molecules <b>1a</b>–<b>g</b> were successfully synthesized in acceptable yields. Their absorption and fluorescence spectra were measured. Among them <b>1c</b>–<b>f</b> are strongly emissive in solutions. Furthermore, <b>1b</b>–<b>f</b> are also fluorescent in their solid states; in particular, <b>1b</b> exhibits a typical aggregation-induced enhanced emission feature. Yellow-emissive microfibrils of <b>1d</b> show potential optical waveguide behavior. HOMO/LUMO energies of <b>1a</b>–<b>f</b> were determined based on their cyclic voltammograms. The results also reveal that HOMO/LUMO energies of these new conjugated molecules are influenced by the two flanking moieties. Notably, the thin film of <b>1c</b> that is emissive shows <i>p</i>-type semiconducting behavior with hole mobility up to 0.0063 cm² V^–1 s^–1 based on the transfer and output characteristics of the OFET (organic field effect transistor)