Search

Mobility is an important parameter to estimate the performance of organic thin‐film transistors, one of the key factors affecting the mobility is the first several semiconductors molecular layers near the insulator surface. A strategy is proposed to introduce aromatic‐rings in the gate insulating layer to modulate the growth of pentacene, thus a series of aryl group containing polymers by reversible‐addition‐fragmentation chain‐transfer polymerization is synthesized for the preparation of organic thin‐film transistor insulators. The semiconductor layer is evaporated on the polymer insulators at room temperature. As the inducing function of the aromatic ring, greater weak interactions between dielectric materials and semiconductors by simulation, which makes the initial pentacene layer weak epitaxial growth, therefore pentacene could form better morphology, especially larger crystal domains and uniform thin‐film continuity. The results show that precision design and synthesis of polymer insulator layers provide new methods to achieve high performance of organic thin‐film transistors with easier fabricating process. [ABSTRACT FROM AUTHOR]

We investigate the maximal finite length submodule of the Breuil–Kisin prismatic cohomology of a smooth proper formal scheme over a $p$ -adic ring of integers. This submodule governs pathology phenomena in integral $p$ -adic cohomology theories. Geometric applications include a control, in low degrees and mild ramifications, of (1) the discrepancy between two naturally associated Albanese varieties in characteristic $p$ , and (2) the kernel of the specialization map in $p$ -adic étale cohomology. As an arithmetic application, we study the boundary case of the theory due to Fontaine and Laffaille, Fontaine and Messing, and Kato. Also included is an interesting example, generalized from a construction in Bhatt, Morrow and Scholze's work, which illustrates some of our theoretical results being sharp, and negates a question of Breuil. [ABSTRACT FROM AUTHOR]

Organic photothermal materials have attracted increasing attention because of their structural diversity, flexibility, and compatibility. However, their energy conversion efficiency is limited owing to the narrow absorption spectrum, strong reflection/transmittance, and insufficient nonradiative decay. In this study, two quinoxaline‐based D–A‐D–A‐D‐type molecules with ethyl (BQE) or carboxylate (BQC) substituents were synthesized. Strong intramolecular charge transfer provided both molecules with a broad absorption range of 350–1000 nm. In addition, the high reorganization energy and weak molecular packing of BQE resulted in efficient nonradiative decay. More importantly, the self‐assembly of BQE leads to a textured surface and enhances the light‐trapping efficiency with significantly reduced light reflection/transmittance. Consequently, BQE achieved an impressive solar‐thermal conversion efficiency of 18.16 % under 1.0 kW m−2 irradiation with good photobleaching resistance. Based on this knowledge, the water evaporation rate of 1.2 kg m−2 h−1 was attained for the BQE‐based interfacial evaporation device with an efficiency of 83 % under 1.0 kW m−2 simulated sunlight. Finally, the synergetic integration of solar‐steam and thermoelectric co‐generation devices based on BQE was realized without significantly sacrificing solar‐steam efficiency. This underscores the practical applications of BQE‐based technology in effectively harnessing photothermal energy. This study provides new insights into the molecular design for enhancing light‐trapping management by molecular self‐assembly, paving the way for photothermal‐driven applications of organic photothermal materials. [ABSTRACT FROM AUTHOR]

Organic photothermal materials have attracted increasing attention because of their structural diversity, flexibility, and compatibility. However, their energy conversion efficiency is limited owing to the narrow absorption spectrum, strong reflection/transmittance, and insufficient nonradiative decay. In this study, two quinoxaline‐based D–A‐D–A‐D‐type molecules with ethyl (BQE) or carboxylate (BQC) substituents were synthesized. Strong intramolecular charge transfer provided both molecules with a broad absorption range of 350–1000 nm. In addition, the high reorganization energy and weak molecular packing of BQE resulted in efficient nonradiative decay. More importantly, the self‐assembly of BQE leads to a textured surface and enhances the light‐trapping efficiency with significantly reduced light reflection/transmittance. Consequently, BQE achieved an impressive solar‐thermal conversion efficiency of 18.16 % under 1.0 kW m−2 irradiation with good photobleaching resistance. Based on this knowledge, the water evaporation rate of 1.2 kg m−2 h−1 was attained for the BQE‐based interfacial evaporation device with an efficiency of 83 % under 1.0 kW m−2 simulated sunlight. Finally, the synergetic integration of solar‐steam and thermoelectric co‐generation devices based on BQE was realized without significantly sacrificing solar‐steam efficiency. This underscores the practical applications of BQE‐based technology in effectively harnessing photothermal energy. This study provides new insights into the molecular design for enhancing light‐trapping management by molecular self‐assembly, paving the way for photothermal‐driven applications of organic photothermal materials. [ABSTRACT FROM AUTHOR]

Low mobility and high operating voltages are bottlenecks in the practical application of ferroelectric organic field-effect transistor (Fe-OFET) nonvolatile memory (NVM). In this article, we demonstrate a high-mobility polymer semiconductor-based Fe-OFET NVM that can well operate at low programming/erasing voltages (VP/VE). The issue that hinders the reduction of the VP/VE in Fe-OFET NVMs is discussed. We develop a route to resolve the issue by building a thin bilayer gate insulator consisted of an ultrathin poly(methyl methacrylate) (PMMA) and a thin poly(vinylidenefluoride-trifluoroethylene) films. The processing compatibility, that is, the tri-layered core architecture consisting of polymer semiconductor and insulator films is prepared by a full-solution technology, is confirmed. The mechanism of the performance improvements by using the ultrathin PMMA in the Fe-OFET NVMs is investigated. As a result, the Fe-OFET NVM exhibits excellent performances at low VP/VE of ±15 V, with a high mobility up to 1.75 cm2/Vs, reliable memory endurance over 400 cycles, and stable memory retention over 65000 s. [ABSTRACT FROM AUTHOR]

The structural, electronic, vibrational, mechanical and thermodynamic properties of Rh5B4 have been investigated within the framework of the density functional theory (DFT) and the direct method using first-principles calculations. The calculated lattice parameters are in good agreement with the available experimental data. The electronic structure suggests that Rh5B4 should exhibit the metallic behavior and hybridizations exist between Rh- d and B- s, B- p orbitals, which illuminates that the bonding between them has certain covalent character. Mechanical properties including elastic constants, bulk modulus, shear modulus, Young's modulus, and Poisson's ratio are calculated. Phonon dispersions and phonon density of states (DOS) are obtained, respectively. Our results indicate that Rh5B4 is dynamically and mechanically stable with better ductility ( B/ G = 3.28) at ambient pressure. In addition, the phonon frequencies at the center ( point) of the first Brillouin zone are predicted and Raman-active and infrared-active modes are also assigned. Finally, the phonon contribution to the Helmholtz free energy F, the phonon contribution to the internal energy E, the constant volume specific heat Cv and vibrational entropy S are studied over the range 0 1000 K. [ABSTRACT FROM AUTHOR]

Ferroelectric organic field-effect transistor nonvolatile memories (Fe-OFET-NVMs) offer attractive features for future memory applications, such as flexible and wearable electronics. Polymer semiconductor-based top-gate Fe-OFET-NVMs possess natural advantages in the device structure and processing manufacturing, compared to small-molecule semiconductor-based bottom-gate Fe-OFET-NVMs. However, their performances, such as mobility and operating voltages, should be further improved to be comparable to those of the latter. In this Letter, we develop a route to achieve high-performance top-gate Fe-OFET-NVMs, by employing a polymer semiconductor channel and self-organized ferroelectric/dielectric gate insulators, which were processed by a solution spin-coating technique. The optimal Fe-OFET-NVM exhibits a high mobility of 1.96 cm2/V s on average, a reliable endurance over 400 cycles, a stable retention capability over 6 × 104 s, and a life more than one year. Furthermore, the operating voltage of the Fe-OFET-NVM is reduced to ±20 V by scaling down the thickness of the ferroelectric/dielectric gate insulator. The whole performances of our memories are comparable to or better than those of the previous Fe-OFET-NVMs. [ABSTRACT FROM AUTHOR]

Flexible floating-gate structural organic thin-film transistor (FG-OTFT) nonvolatile memories (NVMs) are demonstrated based on an integrated molecular floating-gate/tunneling (I-FG/T) layer and a pn-heterojunction channel layer. Semiconducting polymer poly(9,9-dioctylfluorene-co-benzothiadiazole) nanoparticles and insulating polymer polystyrene are used to build the I-FG/T layers by spin-coating their solution. The dependence of the memory performances on the structure of I-FG/T layers is researched. For achieving a large charge storage capacity, the pn-heterojunction channel, consisting of 2,9-didecyldinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene and F16CuPc, is fabricated to provide both electrons and holes for injecting and trapping in the floating gate by overwriting the stored charges with an opposite polarity at the programming and erasing voltages, respectively. As an optimal result, a high performance flexible FG-OTFT NVM is achieved, with a large memory window of 21.6 V on average, a highly stable charge storage retention capability up to 10 years, and a highly reliable programming/erasing switching endurance over 200 cycles. The FG-OTFT NVM also exhibits an excellent mechanical bending durability with the memory performances maintaining well over 6000 bending cycles at a bending radius of 5.9 mm. [ABSTRACT FROM AUTHOR]

Floating-gate based organic field-effect transistor (FG-OFET) nonvolatile memories (NVMs) are demonstrated based on an integrated molecular floating-gate/tunneling layer, in which small molecular fullerene (C60) acting as the floating-gate and long-chain alkane molecule tetratetracontane acting as the tunneling layer are synchronously prepared by vacuum thermal evaporation. The effects of the thickness and the component of the integrated floating-gate/tunneling layer on the performances of memory are investigated. As a result, a high performance FG-OFET NVM is achieved, with a large memory window of 8.0 V on average, stable retention capability over 10 years, and reliable switching endurance over 100 cycles at the programming/erasing voltages of ±40 V, at an optimized condition. [ABSTRACT FROM AUTHOR]