Gel Polymer Electrolytes for Lithium-Ion Batteries Enabled by Photo Crosslinked Polymer Network.

We demonstrate a gel polymer electrolyte (GPE) featuring a crosslinked polymer matrix formed by poly(ethylene glycol) diacrylate (PEGDA) and dipentaerythritol hexaacrylate (DPHA) using the radical photo initiator via ultraviolet (UV) photopolymerization for lithium-ion batteries. The two monomers with acrylate functional groups undergo chemical crosslinking, resulting in a three-dimensional structure capable of absorbing liquid electrolytes to form a gel. The GPE system was strategically designed by varying the ratios between the main polymer backbone (PEGDA) and the crosslinker (DPHA) to achieve an optimal gel polymer electrolyte network. The resulting GPE exhibited enhanced thermal stability compared to conventional liquid electrolytes (LE) and demonstrated high ionic conductivity (1.40 mS/cm) with a high lithium transference number of 0.65. Moreover, the obtained GPE displayed exceptional cycle performance, maintaining a higher capacity retention (85.2%) comparable to the cell with LE (79.3%) after 200 cycles.

In Situ Radiation Hardness Study of Amorphous Zn-In-Sn-O Thin-Film Transistors with Structural Plasticity and Defect Tolerance.

Solution-processed metal-oxide thin-film transistors (TFTs) with different metal compositions are investigated for ex situ and in situ radiation hardness experiments against ionizing radiation exposure. The synergetic combination of structural plasticity of Zn, defect tolerance of Sn, and high electron mobility of In identifies amorphous zinc-indium-tin oxide (Zn-In-Sn-O or ZITO) as an optimal radiation-resistant channel layer of TFTs. The ZITO with an elemental blending ratio of 4:1:1 for Zn/In/Sn exhibits superior ex situ radiation resistance compared to In-Ga-Zn-O, Ga-Sn-O, Ga-In-Sn-O, and Ga-Sn-Zn-O. Based on the in situ irradiation results, where a negative threshold voltage shifts and a mobility increase as well as both off current and leakage current increase are observed, three factors are proposed for the degradation mechanisms: (i) increase of channel conductivity, (ii) interface-trapped and dielectric-trapped charge buildup, and (iii) trap-assisted tunneling in the dielectric. Finally, in situ radiation-hard oxide-based TFTs are demonstrated by employing a radiation-resistant ZITO channel, a thin dielectric (50 nm SiO2), and a passivation layer (PCBM for ambient exposure), which exhibit excellent stability with an electron mobility of ∼10 cm2/V s and aΔVth of <3 V under real-time (15 kGy/h) gamma-ray irradiation in an ambient atmosphere.

Development and Characterization of Solution-Processable Dithieno[3,2-b : 2',3'-d]thiophenes Derivatives with Various End-capped Groups for Organic Field-Effect Transistors.

In this paper, four organic materials based on dithieno[3,2-b : 2',3'-d]thiophene (DTT) core structure with end-capping groups (phenyl and thienyl) and linker (acetylenic and olefinic) between DTT-core and end-capping groups were synthesized and characterized as solution-processable organic semiconductors (OSCs) for organic field-effect transistors (OFETs). Thermal, optical, and electrochemical properties of the corresponding materials were determined. Next, all DTT-derivatives were coated by solution-shearing method, and the thin-film microstructures and morphologies were investigated. To investigate the electrical performance of four newly synthesized DTT-derivatives, bottom-gate/top-contact OFETs were fabricated and characterized in ambient condition. It was found that substitution of acetylenic for olefinic linkers between DTT-cores and end-capping groups enhanced device performance. Especially, the resulting OFETs based on the compound containing phenylacetylene exhibited the highest hole mobility of 0.15 cm2 /Vs and current on/off ratio of ∼106 , consistent with film morphology and texture showing long range interconnected crystalline grains and strong diffraction peaks.

Synthesis, Characterization, and Thin-Film Transistor Response of Benzo[i]pentahelicene-3,6-dione.

Organic semiconductors hold the promise of simple, large area solution deposition, low thermal budgets as well as compatibility with flexible substrates, thus emerging as viable alternatives for cost-effective (opto)-electronic devices. In this study, we report the optimized synthesis and characterization of a helically shaped polycyclic aromatic compound, namely benzo[i]pentahelicene-3,6-dione, and explored its use in the fabrication of organic field effect transistors. In addition, we investigated its thermal, optical absorption, and electrochemical properties. Finally, the single crystal X-ray characterization is reported.

High Throughput Bar-Coating Processed Organic-Inorganic Hybrid Multi-Layers for Gas Barrier Thin-Films.

Herein, we demonstrate the preparation of a scalable bar-coated nanocomposite organic-inorganic hybrid film and developed robust barrier films for general purpose packaging. Using combinatory printing of polymers and nanocomposites by bar coating, a facile and effective barrier film fabrication method was developed. Based on a preliminary survey with several material combinations, a rationalized two-fold nanocomposite film was fabricated. The number of layers in the barrier film significantly modified oxygen barrier performance such that, for the 1 wt% ethylene vinyl alcohol (EVOH) intercalated film, the oxygen transmission rate (OTR) of the 5-layer sample was reduced to 31.69% of the OTR of the 3-layer sample (112.8 vs. 35.75 cc/(m² · day)). In addition, fine tuning the amount of EVOH polymer enabled further improvement of oxygen barrier performance. Intercalation of 2 wt% EVOH resulted an OTR improvement from 35.75 in the 1 wt% sample to 11.90 cc/(m² ·day), which is a 4.25-fold enhancement. Overall barrier characteristics proved that our approach could be used for large-area deposited, oxygen resistant, general purpose packaging applications.

Solution-Processed Nonvolatile Organic Transistor Memory Based on Semiconductor Blends.

Solution-processed nonvolatile organic transistor memory devices are fabricated by employing semiconductor blends of p-channel 6,13-bis(triisopropylsilylethynyl)pentacene and n-channel poly{[ N, N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]- alt-5,5'-(2,2'-bithiophene)} (P(NDI2OD-2T); N2200) on polystyrene-brush as a polymer electret. Electret-based memory characteristics are significantly changed depending on the frontier molecular orbitals of the active semiconductors because the charge-trapping efficiency is mainly determined by the energy barrier to transfer electrons and holes from the active channel to the electret layer. A semiconductor mixture with an optimized blending ratio results in an efficient programming and erasing process. Thus, we obtained a remarkably high ratio of ON/OFF current (memory ratio) about 107 and a large amount of shifts in the threshold voltage (memory window) between the programmed and erased states of 55 V, while single-component N2200 showed only writing-once-read-many (WORM)-type memory. Especially, the programmed data can be stably retained more than 10 years with a sufficient memory ratio of 103. Furthermore, our semiconductor blend system leads to preferable vertical phase separation, which affords good reliability under a sequential memory operation condition as well as stability in ambient air. It is expected that our memory devices can be applied for versatile data storage in printed and flexible electronic applications.

A Solution-Processable meso-Phenyl-BODIPY-Based n-Channel Semiconductor with Enhanced Fluorescence Emission.

The molecular design, synthesis, and characterization of an acceptor-donor-acceptor (A-D-A) semiconductor BDY-Ph-2T-Ph-BDY comprising a central phenyl-bithiophene-phenyl π-donor and BODIPY π-acceptor end-units is reported. The semiconductor shows an optical band gap of 2.32 eV with a highly stabilized HOMO/LUMO (-5.74 eV/-3.42 eV). Single-crystal X-ray diffraction (XRD) reveals D-A dihedral angle of ca. 66° and strong intermolecular "C-H ⋅⋅⋅ π (3.31 Å)" interactions. Reduced π-donor strength, increased D-A dihedral angle, and restricted intramolecular D-A rotations allows for both good fluorescence efficiency (ΦF =0.30) and n-channel OFET transport (µe =0.005 cm2 /V ⋅ s; Ion /Ioff =104 -105 ). This indicates a much improved (6-fold) fluorescence quantum yield compared to the meso-thienyl BODIPY semiconductor BDY-4T-BDY. Photophysical studies reveal important transitions between locally excited (LE) and twisted intramolecular charge-transfer (TICT) states in solution and the solid state, which could be controlled by solvent polarity and nano-aggregation. This is the first report of such high emissive characteristics for a BODIPY-based n-channel semiconductor.

BODIPY-Based Semiconducting Materials for Organic Bulk Heterojunction Photovoltaics and Thin-Film Transistors.

The rapid emergence of organic (opto)electronics as a promising alternative to conventional (opto)electronics has been achieved through the design and development of novel π-conjugated systems. Among various semiconducting structural platforms, 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) π-systems have recently attracted attention for use in organic thin-films transistors (OTFTs) and organic photovoltaics (OPVs). This Review article provides an overview of the developments in the past 10 years on the structural design and synthesis of BODIPY-based organic semiconductors and their application in OTFT/OPV devices. The findings summarized and discussed here include the most recent breakthroughs in BODIPYs with record-high charge carrier mobilities and power conversion efficiencies (PCEs). The most up-to-date design rationales and discussions providing a strong understanding of structure-property-function relationships in BODIPY-based semiconductors are presented. Thus, this review is expected to inspire new research for future materials developments/applications in this family of molecules.

Solution-Processable Diketopyrrolopyrrole Derivatives as Organic Semiconductors for Organic Thin-Film Transistors.

Solution-processable diketopyrrolopyrrole derivatives having acetylene, 2,5-bis(2-ethylhexyl)-3-(5-(phenylethynyl)thiophen-2-yl)-6-(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (3), 2,5-bis (2-ethylhexyl)-3-(thiophen-2-yl)-6-(5-(thiophen-2-ylethynyl)thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c] pyrrole-1,4-dione (4), and 6,6'-((thiophene-2,5-diylbis(ethyne-2,1-diyl))bis(thiophene-5,2-diyl)) bis(2,5-bis(2-ethylhexyl)-3-(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione) (5) were synthesized and characterized as organic semiconductors for organic thin-film transistors (OTFTs). For the fabrication of thin films based on solution processable compounds, drop-casting (DC) and solution-shearing (SS) were employed. Thin films of compound 5 exhibited p-channel characteristics with carrier mobility as high as 5.7 × 10-4 cm2/Vs and a current on/off ratio of 104-106 for top-contact/bottom-gate OTFT devices.

Multifunctional Organic-Semiconductor Interfacial Layers for Solution-Processed Oxide-Semiconductor Thin-Film Transistor.

The stabilization and control of the electrical properties in solution-processed amorphous-oxide semiconductors (AOSs) is crucial for the realization of cost-effective, high-performance, large-area electronics. In particular, impurity diffusion, electrical instability, and the lack of a general substitutional doping strategy for the active layer hinder the industrial implementation of copper electrodes and the fine tuning of the electrical parameters of AOS-based thin-film transistors (TFTs). In this study, the authors employ a multifunctional organic-semiconductor (OSC) interlayer as a solution-processed thin-film passivation layer and a charge-transfer dopant. As an electrically active impurity blocking layer, the OSC interlayer enhances the electrical stability of AOS TFTs by suppressing the adsorption of environmental gas species and copper-ion diffusion. Moreover, charge transfer between the organic interlayer and the AOS allows the fine tuning of the electrical properties and the passivation of the electrical defects in the AOS TFTs. The development of a multifunctional solution-processed organic interlayer enables the production of low-cost, high-performance oxide semiconductor-based circuits.

Effect of methane-sugar interaction on the solubility of methane in an aqueous solution.

In this study, the effect of methane-sugar interaction on the solubility of methane in an aqueous solution at ambient pressure was investigated. Various sugars, such as fructose, glucose, sucrose, maltose, and raffinose, were used, and depending on the type and concentration of sugar, the methane solubility increased from 21.72mg/L (in pure water) to 24.86mg/L. Sugars with a low hydrogen-bonding number between the water and sugar molecules exhibited a large enhancement in methane solubility. The solute partitioning model and molecular dynamics simulations were employed to verify the results obtained for the experimental solubility of methane in aqueous sugar solutions.

A Solution-Processable Liquid-Crystalline Semiconductor for Low-Temperature-Annealed Air-Stable N-Channel Field-Effect Transistors.

A new solution-processable and air-stable liquid-crystalline n-channel organic semiconductor (2,2'-(2,8-bis(5-(2-octyldodecyl)thiophen-2-yl)indeno[1,2-b]fluorene-6,12-diylidene)dimalononitrile, α,ω-2OD-TIFDMT) with donor-acceptor-donor (D-A-D) π conjugation has been designed, synthesized, and fully characterized. The new semiconductor exhibits a low LUMO energy (-4.19 eV) and a narrow optical bandgap (1.35 eV). The typical pseudo-focal-conic fan-shaped texture of a hexagonal columnar liquid-crystalline (LC) phase was observed over a wide temperature range. The spin-coated semiconductor thin films show the formation of large (≈0.5-1 µm) and highly crystalline platelike grains with edge-on molecular orientations. Low-temperature-annealed (50 °C) top-contact/bottom-gate OFETs have provided good electron mobility values as high as 0.11 cm2 (V s)-1 and high Ion /Ioff ratios of 107 to 108 with excellent ambient stability. This indicates an enhancement of two orders of magnitude (100×) when compared with the ß-substituted parent semiconductor, ß-DD-TIFDMT (2,2'-(2,8-bis(3-dodecylthiophen-2-yl)indeno[1,2-b]fluorene-6,12-diylidene)dimalononitrile). The current rational alkyl-chain engineering route offers great advantages for D-A-D π-core coplanarity in addition to maintaining good solubility in organic solvents, and leads to favorable optoelectronic/physicochemical characteristics. These remarkable findings demonstrate that α,ω-2OD-TIFDMT is a promising semiconductor material for the development of n-channel OFETs on flexible plastic substrates and LC-state annealing of the columnar liquid crystals can lower the electron mobility for transistor-type charge transport.

Benzothiadiazole-Based Small-Molecule Semiconductors for Organic Thin-Film Transistors and Complementary-like Inverters.

New benzothiadiazole derivatives, 4,7-bis(5-phenylthiophen-2-yl)benzo[c][1,2,5]thiadiazole (PT-BTD) and 4,7-bis[4-(thiophen-2-yl)phenyl]benzo[c][1,2,5]thiadiazole (TP-BTD), were synthesized and characterized as small-molecule organic semiconductors for organic thin-film transistors (OTFTs) and complementary inverters. The thermal, optical, and electrochemical properties of the new compounds were fully characterized. Vacuum-deposition and solution-shearing methods were used to fabricate thin films based on these compounds. Thin films based on PT-BTD exhibited p-channel characteristics with hole mobilities as high as 0.10 cm2 V-1 s-1 and current on/off ratios >107 for top-contact/bottom-gate OTFT devices. With an optimized blending ratio of PT-BTD and the representative n-channel semiconductor N,N'-1H,1H-perfluorobutyl dicyanoperylenediimide, bulk heterojunction ambipolar transistors were fabricated with balanced hole and electron mobilities of 0.10 and 0.07 cm2 V-1 s-1 , respectively. Furthermore, a complementary-like inverter was fabricated using ambipolar thin-film transistors, which showed a high voltage gain of 84.

Novel Organic Semiconductors Based on Phenyl and Phenylthienyl Derivatives for Organic Thin-Film Transistors.

New phenyl and phenylthienyl derivatives end-functionalized with carbazole and α-carboline, 9-(4- (9H-carbazol-9-yl)phenyl)-9H-carbazole, 9-(4-(9H-carbazol-9-yl)phenyl)-9H-pyrido[2,3-b]indole, 9-(3-(9H-carbazol-9-yl)phenyl)-9H-carbazole, 9-(3-(9H-carbazol-9-yl)phenyl)-9H-pyrido[2,3-b]indole, 9-(4-(5-(9H-carbazol-9-yl)thiophen-2-yl)phenyl)-9H-carbazole, and 9-(3-(5-(9H-carbazo-9-yl) thiophen-2-yl)phenyl)-9H-carbazole were synthesized and characterized as organic semiconductors for organic thin-film transistors (OTFTs). Most compounds exhibited p-channel characteristics with carrier mobility as high as 1.7 x 10⁻5 cm²/Vs and a current on/off ratio of 10²-104 for top-contact/bottom-gate OTFT devices.

Synthesis and Characterization of Benzothiadiazole Derivatives as Organic Semiconductors for Organic Thin-Film Transistors.

New benzothiadiazole derivatives end-functionalized with carbazole and a-carboline, 4,7-di(9H-carbazol-9-yl)benzo[c][1,2,5]thiadiazole (1) and 4-(9H-carbazol-9-yl)-7-(9H-pyrido[2,3-bindol-9-yl) benzo[c][1,2,5]thiadiazole (2) were synthesized and characterized as organic semiconductors for organic thin-film transistors (OTFTs). Thermal, optical, and electrochemical properties of the corresoponding compounds were characterized. Thin films of compound 1 exhibited p-channel characteristics with carrier mobility as high as 10⁻4 cm²/Vs and a current on/off ratio of 105 for top-contact/bottom-gate OTFT devices.

Solution-Processable BODIPY-Based Small Molecules for Semiconducting Microfibers in Organic Thin-Film Transistors.

Electron-deficient π-conjugated small molecules can function as electron-transporting semiconductors in various optoelectronic applications. Despite their unique structural, optical, and electronic properties, the development of BODIPY-based organic semiconductors has lagged behind that of other π-deficient units. Here, we report the design and synthesis of two novel solution-proccessable BODIPY-based small molecules (BDY-3T-BDY and BDY-4T-BDY) for organic thin-film transistors (OTFTs). The new semiconductors were fully characterized by (1)H/(13)C NMR, mass spectrometry, cyclic voltammetry, UV-vis spectroscopy, photoluminescence, differential scanning calorimetry, and thermogravimetric analysis. The single-crystal X-ray diffraction (XRD) characterization of a key intermediate reveals crucial structural properties. Solution-sheared top-contact/bottom-gate OTFTs exhibited electron mobilities up to 0.01 cm(2)/V·s and current on/off ratios of >10(8). Film microstructural and morphological characterizations indicate the formation of relatively long (∼0.1 mm) and micrometer-sized (1-2 µm) crystalline fibers for BDY-4T-BDY-based films along the shearing direction. Fiber-alignment-induced charge-transport anisotropy (µâˆ¥/µâŠ¥ ≈ 10) was observed, and higher mobilities were achieved when the microfibers were aligned along the conduction channel, which allows for efficient long-range charge-transport between source and drain electrodes. These OTFT performances are the highest reported to date for a BODIPY-based molecular semiconductor, and demonstrate that BODIPY is a promising building block for enabling solution-processed, electron-transporting semiconductor films.

Biocatalytic conversion of methane to methanol as a key step for development of methane-based biorefineries.

Methane is considered as a next-generation carbon feedstock owing to the vast reserves of natural and shale gas. Methane can be converted to methanol by various methods, which in turn can be used as a starting chemical for the production of value-added chemicals using existing chemical conversion processes. Methane monooxygenase is the key enzyme that catalyzes the addition of oxygen to methane. Methanotrophic bacteria can transform methane to methanol by inhibiting methanol dehydrogenase. In this paper, we review the recent progress made on the biocatalytic conversion of methane to methanol as a key step for methane-based refinery systems and discuss future prospects for this technology.

Enhanced performance of solution-processed TESPE-ADT thin-film transistors.

A solution-processed anthradithiophene derivative, 5,11-bis(4-triethylsilylphenylethynyl)anthradithiophene (TESPE-ADT), is studied for use as the semiconducting material in thin-film transistors (TFTs). To enhance the electrical performance of the devices, two different kinds of solution processing (spin-coating and drop-casting) on various gate dielectrics as well as additional post-treatment are employed on thin films of TESPE-ADT, and p-channel OTFT transport with hole mobilities as high as ~0.12 cm(2) V(-1) s(-1) are achieved. The film morphologies and formed microstructures of the semiconductor films are characterized in terms of film processing conditions and are correlated with variations in device performance.

Enhanced performance of benzothieno[3,2-b]thiophene (BTT)-based bottom-contact thin-film transistors.

Three new benzothieno[3,2-b]thiophene (BTT; 1) derivatives, which were end-functionalized with phenyl (BTT-P; 2), benzothiophenyl (BTT-BT; 3), and benzothieno[3,2-b]thiophenyl groups (BBTT; 4; dimer of 1), were synthesized and characterized in organic thin-film transistors (OTFTs). A new and improved synthetic method for BTTs was developed, which enabled the efficient realization of new BTT-based semiconductors. The crystal structure of BBTT was determined by single-crystal X-ray diffraction. Within this family, BBTT, which had the largest conjugation of the BTT derivatives in this study, exhibited the highest p-channel characteristic, with a carrier mobility as high as 0.22 cm(2) V(-1) s(-1) and a current on/off ratio of 1×10(7) , as well as good ambient stability for bottom-contact/bottom-gate OTFT devices. The device characteristics were correlated with the film morphologies and microstructures of the corresponding compounds.

High-performance bottom-contact organic thin-film transistors based on benzo[d,d']thieno[3,2-b;4,5-b']dithiophenes (BTDTs) derivatives.

Three benzo[d,d']thieno[3,2-b;4,5-b']dithiophene (BTDT) derivatives, end-functionalized with benzothiophenyl (BT-BTDT; 2), benzothieno[3,2-b]thiophenyl (BTT-BTDT; 3), and benzo[d,d']thieno[3,2-b;4,5-b']dithiophenyl (BBTDT; 4), were prepared for bottom-contact/bottom-gate organic thin-film transistors (OTFTs). An improved one-pot [2 + 1 + 1] synthetic method of BTDT with improved synthetic yield was achieved, which enabled the efficient realization of new BTDT-based semiconductors. All of the BTDT compounds exhibited high performance p-channel characteristics with carrier mobilities as high as 0.34 cm(2)/(V s) and a current on/off ratio of 1 × 10(7), as well as enhanced ambient stability. The device characteristics have been correlated with the film morphologies and microstructures of the corresponding compounds.