Asymmetric Alkylthienyl Thienoacenes Derived from Anthra[2,3‑<i>b</i>]thieno[2,3‑<i>d</i>]thiophene for Solution-Processable Organic Semiconductors

Anthra­[2,3-<i>b</i>]­thieno­[2,3-<i>d</i>]­thiophene (ATT), which is readily accessed from thieno­[3,2-<i>b</i>]­thiophene and 2,3-naphthalenedicarboxylic anhydride, allows for selective substitution at the terminal thiophene ring, thereby providing asymmetric monoalkyl and monoalkylthienyl thienoacenes. Alkyl-substituted ATT (CnATT, <i>n</i> = 6, 8, 10, 12) has characteristics of a p-type field-effect transistor (FET), with mobility on the order of 0.01 cm² V^–1 s^–1, which is the same as ATT. Conversely, alkylthienyl-substituted ATT (CnTATT, <i>n</i> = 6, 8, 10, 12) exhibits FET mobility of 0.15–1.9 cm² V^–1 s^–1, which is up to 2 orders of magnitude greater than that of ATT and CnATT. Moreover, CnTATT forms crystalline thin films both by spin coating and drop casting, and C8TATT in particular exhibits a mobility of up to 1.6 cm² V^–1 s^–1 in the drop-cast film. X-ray diffraction patterns of CnTATT thin films indicate that the molecules become oriented edge-on at the substrate surface with a highly ordered structure in the in-plane direction. Accordingly, CnTATT serves as a solution-processable p-type organic field-effect transistor, where the additional thiophene ring contributes significantly to the highly ordered thin-film structure and the high carrier mobility

Asymmetric Alkylthienyl Thienoacenes Derived from Anthra[2,3‑<i>b</i>]thieno[2,3‑<i>d</i>]thiophene for Solution-Processable Organic Semiconductors

Anthra­[2,3-<i>b</i>]­thieno­[2,3-<i>d</i>]­thiophene (ATT), which is readily accessed from thieno­[3,2-<i>b</i>]­thiophene and 2,3-naphthalenedicarboxylic anhydride, allows for selective substitution at the terminal thiophene ring, thereby providing asymmetric monoalkyl and monoalkylthienyl thienoacenes. Alkyl-substituted ATT (CnATT, <i>n</i> = 6, 8, 10, 12) has characteristics of a p-type field-effect transistor (FET), with mobility on the order of 0.01 cm² V^–1 s^–1, which is the same as ATT. Conversely, alkylthienyl-substituted ATT (CnTATT, <i>n</i> = 6, 8, 10, 12) exhibits FET mobility of 0.15–1.9 cm² V^–1 s^–1, which is up to 2 orders of magnitude greater than that of ATT and CnATT. Moreover, CnTATT forms crystalline thin films both by spin coating and drop casting, and C8TATT in particular exhibits a mobility of up to 1.6 cm² V^–1 s^–1 in the drop-cast film. X-ray diffraction patterns of CnTATT thin films indicate that the molecules become oriented edge-on at the substrate surface with a highly ordered structure in the in-plane direction. Accordingly, CnTATT serves as a solution-processable p-type organic field-effect transistor, where the additional thiophene ring contributes significantly to the highly ordered thin-film structure and the high carrier mobility

Electrochemical Self-Assembly of Nanostructured CuSCN/Rhodamine B Hybrid Thin Film and Its Dye-Sensitized Photocathodic Properties

Nanostructured hybrid thin films of CuSCN and rhodamine B (RB) are electrochemically self-assembled (ESA) by cathodic electrolysis in an ethanol/water mixture containing Cu²⁺, SCN^–, and RB. By selecting the solvent, Cu²⁺/SCN^– ratio, and the concentration of RB, we demonstrate several control parameters in the film formation. High loading of RB into the film has been achieved to reach a CuSCN:RB volume ratio of approximately 2:1. The RB solid could almost completely be extracted from the hybrid film by soaking the film in dimethylacetamide (DMA), leading to a large increase of the surface area. The crystallographic orientation of the nanostructure with respect to the substrate can be controlled. Efficient quenching of fluorescence of RB has been observed for the CuSCN/RB hybrid film, implying hole injection from RB excited state to CuSCN. Photoelectrochemical study on the porous crystalline CuSCN obtained after the DMA treatment and sensitized with RB revealed sensitized photocathodic action under visible light illumination, indicating the potential usefulness of the porous CuSCN electrodes for construction of tandem dye-sensitized solar cells

Host Cell Prediction of Exosomes Using Morphological Features on Solid Surfaces Analyzed by Machine Learning

Exosomes are extracellular nanovesicles released from any cells and found in any body fluid. Because exosomes exhibit information of their host cells (secreting cells), their analysis is expected to be a powerful tool for early diagnosis of cancers. To predict the host cells, we extracted multidimensional feature data about size, shape, and deformation of exosomes immobilized on solid surfaces by atomic force microscopy (AFM). The key idea is combination of support vector machine (SVM) learning for individual exosome particles and their interpretation by principal component analysis (PCA). We observed exosomes derived from three different cancer cells on SiO₂/Si, 3-aminopropyltriethoxysilane-modified-SiO₂/Si, and TiO₂ substrates by AFM. Then, 14-dimensional feature vectors were extracted from AFM particle data, and classifiers were trained in 14-dimensional space. The prediction accuracy for host cells of test AFM particles was examined by the cross-validation test. As a result, we obtained prediction of exosome host cells with the best accuracy of 85.2% for two-class SVM learning and 82.6% for three-class one. By PCA of the particle classifiers, we concluded that the main factors for prediction accuracy and its strong dependence on substrates are incremental decrease in the PCA-defined aspect ratio of the particles with their volume