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Two low-bandgap (LGB) conjugated polymers ( P1 and P2) based on thiophene-phenylene-thiophene (TPT) with adequate energy levels have been designed and synthesized for application in bulk-heterojunction polymer solar cells (PSCs). The absorption spectral, electrochemical, field effect hole mobility and photovoltaic properties of LGB TPT derivatives are investigated and compared with poly(3-hexylthiophene) (P3HT). Photophysical studies reveal bandgaps of 1.76 eV for P1 and 1.70 eV for P2, which could effectively harvest broader solar spectrum. In addition, the thin film absorption coefficients of P1 and P2 are 1.6 x 10 (5) cm (-1) (lambda approximately 520 nm) and 1.4 x 10 (5) cm (-1) (lambda approximately 590 nm), respectively. Electrochemical studies indicate desirable HOMO/LUMO levels that enable a high open circuit voltage while blending them with fullerene derivatives as electron acceptors. Furthermore, both materials show sufficient hole mobility (3.4 x 10 (-3) cm (2)/Vs for P2) allowing efficient charge extraction and a good fill-factor for PSC application. High-performance power conversion efficiency (PCE) of 4.4% is obtained under simulated solar light AM 1.5 G (100 mW/cm (2)) from PSC device with an active layer containing 25 wt% P2 and 75 wt% [6,6]-phenyl-C71-butyric acid methyl ester (PC 71BM), which is superior to that of the analogous P3HT cell (3.9%) under the same experimental condition.

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We have prepared thiophene/phenylene/thiophene (TPT)-based low bandgap conjugated polymers exhibiting tunable energy levels and investigated their application in solar cells. By incorporating various electron-withdrawing comonomers through Stille coupling reactions, we obtained TPT-based donor/acceptor copolymers having bandgaps ranging from 1.0 to 1.8 eV. We compared the absorption spectra, electrochemistry, field effect hole mobility, and photovoltaic properties of these low bandgap TPT derivatives with those of poly(3-hexylthiophene) (P3HT). The absorption coefficients of the thin films fell in the range from 0.77 Â 10 5 to 1.4 Â 10 5 cm -1 . These materials displayed sufficiently high hole mobilities (>10 -3 cm 2 V -1 s -1 ) for efficient charge extraction and good fill-factors for organic photovoltaic applications. Electrochemical studies indicated desirable HOMO/LUMO levels, with a good correlation between the HOMO energy levels and the open circuit voltage (V oc ) when the polymers were blended with fullerene derivative as an electron acceptor. Power conversion efficiencies of up to 4.3% were achieved under AM 1.5G simulated solar light (100 mW cm -2 ). Our findings suggest that TPT derivatives presenting suitable electron-withdrawing groups are promising photovoltaic materials.

Preoperative serum VEGF is a significant independent predictor of tumor recurrence, DFS, and OS in patients with resectable HCC.

The videos on YouTube come either from mass media or are created and uploaded by amateur individuals. This study focused on how amateur individuals explore their digital self and establish parasocial interaction with others via YouTube videos. Drawing upon in-depth interviews with 45 participants (11 females and 34 males), our data demonstrate that YouTube is a consumer narrative where multiple digital selves and parasocial relationships are made comprehensible. It also unfolds the complex process of forming one's digital self and parasocial relationships on YouTube by undergoing three main phases: digital self-construction, digital-self presentation strategies, and parasocial relationship developments that are managed by digital-self images. The results suggest that YouTube is a set of cultural values in terms of symbolic meanings in everyday life that are essential for consumers to digitally self-construct, self-present, and parasocially interact with online viewers.

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Four novel conjugated polymers (P1, P2, P3, and P4) based on coplanar thiophene-phenylenethiophene (TPT) derivatives have been designed and synthesized for application in polymer solar cells (PSCs). The optical, electrochemical, field effect carrier mobility, and photovoltaic properties of P1-P4 are investigated and compared with those of poly(3-hexylthiophene) (P3HT). PSCs are fabricated based on the blend of the polymers and [6,6]-phenyl-C61-butyric acid methyl ester (PC 61 BM) or 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-C-71 (PC 71 BM) with a weight ratio of 1:3. The maximum power conversion efficiency (PCE) of the PSCs based on P3/PC 71 BM system reaches 3.3% with a short circuit current density (J sc ) of 7.6 mA/cm 2 , an open circuit voltage (V oc ) of 0.8 V, and a fill factor (FF) of 0.54 under AM 1.5G (100 mW/cm 2 ) illumination. The results indicate that the coplanar TPT conjugated derivatives are promising PSC materials.