Derivatives of diphenylamine and benzothiadiazole in optoelectronic applications: a review

Light-emitting conjugated organic compounds have found special interest among researchers. Because of their adjustable optoelectronic properties they can be applied in e.g. field-effect transistors, sensors, light-emitting diodes or photovoltaic cells. In order to develop high-performance systems, it is important to understand the relationship between the structure and the photophysical properties of the material used. One of the employed strategies is to decrease the band gap of conjugated compounds, often achieved through a “donor–acceptor” approach. One of the popular groups applied as an electron-accepting unit are benzothiadiazoles, while diphenylamine exhibits good electron-donating ability. The functional groups can affect the energy levels of materials, influencing the color of the light emitted. This work presents a review of research focused on the structure-properties relationship of diphenylamine and benzothiadiazole derivatives with optoelectronic applications.

Synthesis, Characterization, and Thin-Film Transistor Response of Benzo[i]pentahelicene-3,6-dione

Organic semiconductors hold the promise of simple, large area solution deposition, low thermal budgets as well as compatibility with flexible substrates, thus emerging as viable alternatives for cost-effective (opto)-electronic devices. In this study, we report the optimized synthesis and characterization of a helically shaped polycyclic aromatic compound, namely benzo[i]pentahelicene-3,6-dione, and explored its use in the fabrication of organic field effect transistors. In addition, we investigated its thermal, optical absorption, and electrochemical properties. Finally, the single crystal X-ray characterization is reported.

Reversible luminescence tuning behavior in a thermal-stimuli-responsive anthracene-based coordination polymer

A new coordination complex presented a series of structural changes accompanied by photo-fluorescence (PL) changes under different temperature stimuli.

Mechanofluorochromism with Aggregation-Induced Emission (AIE) Characteristics: A Perspective Applying Isotropic and Anisotropic Force

Organic mechanofluorochromic (MFC) materials (that change their emission under anisotropic and isotropic pressure) have attracted a great attention in recent years due to their promising applications in sensing pressure, storage devices, security inks, three-dimensional (3D) printing, etc. Stimuli-responsive organic materials with aggregation-induced emission (AIE) characteristics would be an interesting class of materials to enrich the chemistry of MFC compounds. A diamond anvil cell (DAC) is a small tool that is employed to generate high and uniform pressure on materials over a small area. This article discusses the relationship between the chemical structure of AIE compounds and the change in emission properties under anisotropic (mechanical grinding) and isotropic (hydrostatic) pressure. The luminescent properties of such materials depend on the molecular rearrangement in the lattice, conformational changes, excited state transitions and weak intermolecular interactions. Hence, studying the change in luminescent property of these compounds under varying pressure will provide a deeper understanding of the excited-state properties of various emissive compounds with stress. The development of such materials and studies into the effect of pressure on their luminescence properties are summarized.

Facilely controllable synthesis of copper-benzothiadiazole complexes via solvothermal reactions: exploring the customized synthetic approach by experiments

It is very challenging to transform small organic molecules into customized coordination polymer (CP) because the functionalities with desired properties are greatly influenced by several elements, including the assembly modes of the organic linkers and metal nodes, organic linker functionalization, and defects. Therefore, deep cognition for the molecular-level engineering of CP chemistry is very important. Herein, we obtained five new copper-benzothiadiazole complexes via a controllable synthesis approach: [CuII(L1)(CH3CN)]2 (C1), [CuIBr(L1)]n (C2), [CuI3Br3(L2)2]n (C3), [CuICl(L3)]2 (C4), and [CuIICl2(L3)2] (C5). In the exploration, we successfully modulated the structure of the organic linker and the valence state of the metal nodes as well as the assembly modes of the organic linkers and metal nodes through the facilely controllable solvothermal reaction. The results from our experiments also indicated that the fusing process was driven by a CuII/CuI catalytic cycle. In this pathway, oxygen is the final electron acceptor and the solvent DMSO acts as a co-oxidant. In C2 and C3, the ever-expanding macrocycles were constructed from CuX clusters and organic chromophore linkers, forming interesting 1D chain structures, while the supramolecular macrocycles were assembled through hydrogen bonding expanding to a 3D network of C5. Interestingly, C1-C4 exhibit chromophore-based fluorescence, but are not phosphorescence.