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Three new derivatives containing silane cores, viz. 9,9′,9′′-(((4-(pyridin-3-yl)phenyl)silanetriyl)tris(benzene-4,1-diyl))tris(9H-carbazole) (SiCz3Py1), bis(4-(9H-carbazol-9-yl)phenyl)bis(4-(pyridin-3-yl)phenyl)silane (SiCz2Py2), and 9-(4-(tris(4-(pyridin-3-yl)phenyl)silyl)phenyl)-9H-carbazole (SiCz1Py3), were designed and synthesized. Carbazole as a donor and pyridine as an acceptor were tethered to tetraphenylsilane at different mole ratios. All three host materials showed high glass transition temperatures between 118 and 164 °C, which are different from those of the previous silane-based host materials (e.g., diphenyldi-o-tolylsilane (UGH-1), 1,4-bis(triphenylsilyl)benzene (UGH-2), and 1,3-bis(triphenylsilyl)benzene (UGH-3)). The triplet energies of these three hosts are observed at 2.85–2.90 eV, which is high enough for them to act as blue host materials in thermally activated delayed fluorescence organic light emitting diodes (TADF OLEDs). In particular, SiCz2Py2 and SiCz1Py3 hosted-TADF OLEDs demonstrated excellent performances, with a maximum external quantum efficiency (EQEmax) of 18.7 and 18.8%, respectively. Such good performances of SiCz2Py2 and SiCz1Py3 are originated by suppressing the non-radiative triplet decay and high reverse intersystem crossing (RISC) rate constant for efficient triplet to singlet up-conversion. This work demonstrates that tetraphenylsilane is a promising non-conjugate (i.e., sp3-hybridized) linkage core for developing a variety of high Tg host materials, particularly for blue TADF OLEDs. [ABSTRACT FROM AUTHOR]

We synthesized two types of novel poly(3-alkylthiophene)-free (D)n-b-(A)m conjugated block copolymers: PTQI-block-PNDISs. PTQI-b-PNDIS is the fully conjugated block copolymer, in which the donor block is connected to the acceptor block via a π-conjugated unit. In addition, the donor block was connected to an acceptor block through a non-conjugated alkylene spacer, yielding PTQI-b-PNDISL, which is a partially conjugated block copolymer. The power conversion efficiency (PCE) was 1.54% with an open-circuit voltage of 0.79 V in the single-component polymer solar cell (PSC) based on PTQI-b-PNDISL, better performance than that of the PSC containing PTQI-b-PNDIS (PCE ∼ 0.36%). These results reveal the potential for improving the photovoltaic performance in PSCs by controlling the internal morphology with exploitation of the self-segregating behavior of p- and n-blocks in the film state. [ABSTRACT FROM AUTHOR]

We propose a novel tricyanovinyldihydrofuran (TCF)-based molecule called DBOB-DTCF that is designed and synthesized for application in n-type field-effect transistors (FETs). It can be operated in a stable manner under ambient conditions. DBOB-DTCF is successfully fabricated as crystalline microplates (CMs) because of its capability of self-assembly. A high electron mobility of ∼1.9 cm2 V−1 s−1 is observed for a CM-based FET, measured under ambient conditions. This suggests that TCF is an excellent acceptor unit that organizes air stable n-type organic semiconductors. [ABSTRACT FROM AUTHOR]