Donor-Acceptor Effect of Carbazole-Based Conjugated Polymer Electrets on Photoresponsive Flash Organic Field-Effect Transistor Memories

The molecular structure of polymer electrets is crucial for creating diverse functionalities of organic field-effect transistor (OFET) devices. Herein, a conceptual framework has been applied in this study to design the highly photoresponsive carbazole-based copolymer electret materials for the application of photoresponsive OFET memory. As an electret layer, two 1,8-carbazole-based copolymers were utilized; the copoly(CT) consisted of carbazole as the donor group and thiophene as the π-spacer, whereas the copoly(CBT) was further introduced as an acceptor moiety, benzothiadiazole, for comparison. Both copolymers exhibited efficient visible-light absorption and photoluminescence quenching in the film state, indicating the formation of a considerable number of nonemissive excitons, one of the crucial factors for achieving photoinduced recovery behavior in OFET memories. Compared to copoly(CT) with the pure donor system, faster and more effective photoinduced recovery behavior was discovered in the copoly(CBT) with the conjugated donor-acceptor structure because of the coexistence of the conjugated donor and acceptor groups. Thus, the dissociation of the generated excitons facilitated the stimulating of the unique ambipolar trapping property, resulting in the high-density data storage devices with multilevel current states. In addition, the nonvolatile and durable characteristics demonstrated the feasibility in application of memory and photorecorders.

Prediction of the Synthesis of Spiro Derivatives by Double Intramolecular Aromatic Electrophilic Substitution Using Reactivity Indices

The synthesis of heterocyclic spirobifluorene (SBF) analogs generally requires long and complicated synthetic pathways. Despite this synthetic effort, such structural modification allows the (opto)electronic properties of this remarkable three-dimensional node to be tuned especially for molecular electronic applications. For this reason, the development of a simple, robust, and efficient synthetic methodology to introduce various heterocycles in place of classical phenyl rings in the spirofluorene motif is highly and timely desirable. In this context, we describe herein our efforts to develop a straightforward and efficient synthesis leading to replacement of 2 phenyl rings by various heterocycles in spiro compounds from 2,2'-dibromobenzophenone. As the same procedure to form fully heterocyclic compounds failed, an original theoretical approach based mainly on the uncommon Fukui dual function was developed in order to determine clearly the limitation of this strategy and provide an efficient predictive tool. Indeed, such calculation allows prediction of the thermodynamic and kinetic aspects of the synthesis of spiro derivatives using a double aromatic electrophilic substitution. If this procedure reproduces well our experimental results focused on (heterocyclic) SBF compounds, it can be certainly adapted and generalized to other intramolecular substitutions.

Synthesis of Thieno[3,2-b]indoles via Halogen Dance and Ligand-Controlled One-Pot Sequential Coupling Reaction

A two-pot synthesis of thieno[3,2-b]indole from 2,5-dibromothiophene is described. A halogen dance of 2,5-dibromothiophene was performed with LDA, and subsequent Negishi coupling was performed with 2-iodoaniline derivatives to provide the corresponding coupling products. The resulting two bromo groups have different reactivities, which were utilized for the one-pot Suzuki-Miyaura coupling/intramolecular Buchwald-Hartwig amination to produce thieno[3,2-b]indole via an assisted tandem catalysis that involved in situ ligand exchange.

Triphenylamine based yellowish-orange light emitting organic dyes (donor–π–acceptor) for hybrid WLEDs and OLEDs: synthesis, characterization and theoretical study

Six novel yellowish-orange light emitting dye molecules consisting of an electron deficient phenone (acceptor) linked to triphenylamine (donor), were designed and synthesized.

Synthesis of a dibenzo-BODIPY-incorporating phenothiazine dye as a panchromatic sensitizer for dye-sensitized solar cells

The introduction of dibenzo-BODIPY into a phenothiazine dye led to the production of a panchromatic sensitizer for dye-sensitized solar cells, a cell with the dye showing a PCE (η) value of 7.69%.

Rigid triarylamine donor–π–acceptor porphyrin dyes and their application in dye-sensitized solar cells

Three donor–π–acceptor porphyrin dyes bearing the rigid 5-phenyl-carbazole, 5-phenyl-iminodibenzyl and 5-phenyl-iminostilbene donor groups were synthesized and their performance evaluated in TiO₂ based dye-sensitized solar cells.