We report recent results on the nonradiative decay (NRD) of fluoren-9-ylidene malononitrile (FM) ambipolar derivatives (FMDs). 2,7- and 3,6-disubstituted FMDs present distinctive photophysics. Charge separation was found dominant for excited state relaxation. The radiative decay (RD) is sensitive to changes in temperature and solvent medium only for the case of 3,6-FMDs. Excited state deactivation of carbazole-containing 3,6-FMD (CPAFM36) was exclusively nonradiative in polar solvents with excited state lifetimes shorter than 10 ps. The charge separation/recombination mechanism of the corresponding FMDs is suggested to fall in the inverted Marcus region of electron transfer. Given the electron-withdrawing properties of the FM unit, its ambipolar derivatives are suggested as potential candidates for air-stable organic thin-film transistors and molecular organic photovoltaics.
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http://dx.doi.org/10.1021/jp111431r | DOI Listing |
J Am Chem Soc
January 2025
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
The development of stable and tunable polycyclic aromatic compounds (PACs) is crucial for the advancement of organic optoelectronics. Conventional PACs, such as acenes, often suffer from poor stability due to photooxidation and oligomerization, which are linked to their frontier molecular orbital energy levels. To address these limitations, we designed and synthesized a new class of π-expanded indoloindolizines by merging indole and indolizine moieties into a single polycyclic framework.
View Article and Find Full Text PDFChemphyschem
December 2024
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
A new class of cyclic dipeptide-isatin hybrids was synthesized using 2,5-diketopiperazine and various isatin derivatives bearing flexible chains and extended aromatic rings in a double Knoevenagel condensation process. These new series demonstrate high solubility and good thermal stability with decomposition temperatures exceeding 370 °C, especially the molecular design with efficient space-filling (CI5 and CI6) stabilized columnar liquid crystalline phase. The hole and electron carrier mobility of the CI5 compound, measured using the space charge limited current (SCLC) technique, were found to be 9.
View Article and Find Full Text PDFMicrocirculation
January 2025
Department of Biomedicine, University of Bergen, Bergen, Norway.
Objective: A theoretical understanding of fluid exchange and the role of initial lymph formation in tissues through mathematical/physical modeling is lacking.
Methods: Here, we present three models for tissues rich in negative fixed charges due to glycosaminoglycans interacting with the extracellular matrix.
Results: We first model a lymphatic opening mechanism at relevant hydrations of the interstitium.
Adv Mater
January 2025
Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China.
Energy level alignment at metal/organic semiconductors (OSCs) interface governs electronic processes in organic electronics devices, making its precise determination essential for understanding carrier transport behaviors and optimizing device performance. However, it is proven that accurately characterizing the energy barrier at metal/OSC interface under operational conditions remains challenging due to the technical limitations of traditional methods. Herein, through integrating highly-improved device constructions with an ingenious derivative-assisted data processing method, this study demonstrates an in-device ballistic-electron-emission spectroscopy using hot-electron transistors to accurately characterize the energy barrier at metal/OSC interface under in-operando conditions.
View Article and Find Full Text PDFChem Commun (Camb)
October 2024
Department of Polymers and Functional Materials, CSIR-Indian Institute of Chemical Technology (IICT), Uppal Road, Tarnaka, Hyderabad 500007, India.
For the first time, we present the detailed synthesis, photophysical, electrochemical, host-guest and charge transport properties of spiro[fluorene-9,9'-xanthene] (SFX) and carbazole macrocycle SPS-NR-02. The electron and hole transport values measured using the space charge limited current (SCLC) method resulted in ambipolar charge transport with an electron to hole mobility ratio of 0.39.
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