Search

The extensive application of multilayer ceramic capacitors provides an attractive development for terminal electrode pastes. However, the growing requirement for advanced glass materials used in terminal electrode pastes is substantiated. Therefore, to advance the development of electrode pastes, better development and deeper exploration of glass powder are required. Here, a series of BaO–ZnO–B2O3–SiO2 (BZBS) glasses were prepared by melt‐quenching technique, which are used to investigate the effect of the introduction of BaO on structure and properties of the ZnO–B2O3–SiO2 (ZBS) glass. With the introduction of BaO, the relative amount of [BO4] was much less, which made the glass network structure loosen, decreased the glass transition temperature (Tg) and increased the coefficient of thermal expansion of the glass. The decreasing contact angle was observed on the surface of a barium titanate (BaTiO3) substrate. When the BaO content was around 3–7 mol%, the stability of ZBS glass frit could be strengthened by inhibiting the precipitation of Zn2SiO4 crystal. In addition, to further characterize the effect of glass on terminal electrode paste, BZBS glass powder was adopted to prepare copper electrode paste, which was printed on the BaTiO3 substrate and subsequently fired at 800°C for 10 min. With the related copper paste containing ZBS glass doped with 7 mol% BaO, the optimum value of acid resistance and sheet resistance (1.99 mΩ) were exhibited, at which the coated copper paste formed a dense conducting layer. [ABSTRACT FROM AUTHOR]

BN‐embedded oligomers with different pairs of BN units were synthesized by electrophilic borylation. Up to four pairs of BN units were incorporated in the large polycyclic aromatic hydrocarbons (PAHs). Their geometric, photophysical, electrochemical, and Lewis acidic properties were investigated by X‐ray crystallography, optical spectroscopy, and cyclic voltammetry. The B−N bonds show delocalized double‐bond characteristics and the conjugation can be extended through the trans‐orientated aromatic azaborine units. Calculations reveal the relatively lower aromaticity for the inner azaborine rings in the BN‐embedded PAH oligomers. The frontier orbitals of the longer oligomers are delocalized over the inner aromatic rings. Consequently, the inner moieties of the BN‐embedded PAH oligomers are more active than the outer parts. This is confirmed by a simple oxidation reaction, which has significant effects on the aromaticity and the intramolecular charge‐transfer interactions. [ABSTRACT FROM AUTHOR]

BN‐embedded oligomers with different pairs of BN units were synthesized by electrophilic borylation. Up to four pairs of BN units were incorporated in the large polycyclic aromatic hydrocarbons (PAHs). Their geometric, photophysical, electrochemical, and Lewis acidic properties were investigated by X‐ray crystallography, optical spectroscopy, and cyclic voltammetry. The B−N bonds show delocalized double‐bond characteristics and the conjugation can be extended through the trans‐orientated aromatic azaborine units. Calculations reveal the relatively lower aromaticity for the inner azaborine rings in the BN‐embedded PAH oligomers. The frontier orbitals of the longer oligomers are delocalized over the inner aromatic rings. Consequently, the inner moieties of the BN‐embedded PAH oligomers are more active than the outer parts. This is confirmed by a simple oxidation reaction, which has significant effects on the aromaticity and the intramolecular charge‐transfer interactions. [ABSTRACT FROM AUTHOR]

A series of polycyclic aromatic hydrocarbons (PAHs), consisting of two pairs of BN units, have been designed and their synthesis has been achieved by electrophilic C−H borylation. Two conjugation extension directions can be found in these B2N2‐embedded PAHs. The B2N2‐containing backbone with shorter effective conjugation length is isoelectronic with diaryl‐fused anthracene, whereas the second derivative, with longer effective conjugation length, is isoelectronic with bis(trans‐arylvinyl)benzene. By incorporating different aryl groups, i.e. furyl, thienyl, benzo[b]furyl, and benzo[b]thienyl groups, into the two crossed directions of the B2N2‐embedded PAHs, their electronic and optical properties have been comparatively investigated by photophysical, electrochemical, and theoretical approaches. It is found that both the substituents and their conjugation extension directions have significant effects on the aromatic and photophysical properties of the B2N2‐embedded PAHs. The conjugation extension in the shorter backbone is more pronounced on the effective conjugation length than the longer backbone. Moreover, all the B2N2‐embedded PAHs behave as both Lewis acids and Lewis bases, and reversible photoluminescence switching can be observed by simply neutralizing the added Lewis acid or Lewis base. [ABSTRACT FROM AUTHOR]

The efficient fixation of excess CO2 from the atmosphere to yield value‐added chemicals remains crucial in response to the increasing levels of carbon emission. Coupling enzymatic reactions with electrochemical regeneration of cofactors is a promising technique for fixing CO2, while producing biomass which can be further transformed into biofuels. Herein, a bioelectrocatalytic system was established by depositing crystallites of a mesoporous metal–organic framework (MOF), termed NU‐1006, containing formate dehydrogenase, on a fluorine‐doped tin oxide glass electrode modified with Cp*Rh(2,2′‐bipyridyl‐5,5′‐dicarboxylic acid)Cl2 complex. This system converts CO2 into formic acid at a rate of 79±3.4 mm h−1 with electrochemical regeneration of the nicotinamide adenine dinucleotide cofactor. The MOF–enzyme composite exhibited significantly higher catalyst stability when subjected to non‐native conditions compared to the free enzyme, doubling the formic acid yield. [ABSTRACT FROM AUTHOR]

The efficient fixation of excess CO2 from the atmosphere to yield value‐added chemicals remains crucial in response to the increasing levels of carbon emission. Coupling enzymatic reactions with electrochemical regeneration of cofactors is a promising technique for fixing CO2, while producing biomass which can be further transformed into biofuels. Herein, a bioelectrocatalytic system was established by depositing crystallites of a mesoporous metal–organic framework (MOF), termed NU‐1006, containing formate dehydrogenase, on a fluorine‐doped tin oxide glass electrode modified with Cp*Rh(2,2′‐bipyridyl‐5,5′‐dicarboxylic acid)Cl2 complex. This system converts CO2 into formic acid at a rate of 79±3.4 mm h−1 with electrochemical regeneration of the nicotinamide adenine dinucleotide cofactor. The MOF–enzyme composite exhibited significantly higher catalyst stability when subjected to non‐native conditions compared to the free enzyme, doubling the formic acid yield. [ABSTRACT FROM AUTHOR]

Two series of regioisomeric luminophores that contained a dithieno[2,3- a:3′,2′- c]phenazine (DTP) unit as an electron acceptor have been designed and synthesized. To investigate the effect of substitution pattern on the optoelectronic properties of these luminophores, electron donors ( N, N-dihexylaniline or N, N-dihexyl-4-vinylaniline) were incorporated at the 2,5-, 8,11-, and 9,10-positions of the DTP unit. We found that the optoelectronic properties of the regioisomeric luminophores were greatly affected by the substitution pattern: functionalization at the 8,11-positions of the DTP unit was superior to the other two substitution patterns in extending the effective π-conjugation and strengthening the intramolecular charge-transfer interactions. Moreover, the insertion of vinyl groups between the DTP and N, N-dihexylaniline units narrowed the energy band-gap for isomers 4 and 5. However, hypsochromically shifted absorption and photoluminescence maxima were observed for isomeric luminophore 6, in which electron donors were substituted at the 2,5-positions of the DTP unit. These results should facilitate greater understanding of the structure-property relationships in regioisomeric semiconductors and present a new way to design optoelectronic materials with effective substitution patterns. [ABSTRACT FROM AUTHOR]

A correction to the article "Charge Transfer Through Dithieno[2,3-a:3',2'-c]phenazine: Effect of Substitution Pattern on the Optoelectronic Properties of Regioisomeric Luminophores" is presented.

Abstract: Hybridization of silicon integrated circuits (ICs) with compound semiconductor device arrays are crucial for making functional hybrid chips, which are found to have enormous applications in many areas. Although widely used in manufacturing hybrid chips, the flip‐chip technology suffers from several limitations that are difficult to overcome, especially when the demand is raised to make functional hybrid chips with higher device array density without sacrificing the chip footprint. To address those issues, Beida Jade Bird Display Limited has developed its unique wafer‐level monolithic hybrid integration technology and demonstrated its advantages in making large‐scale hybrid integration of functional device arrays on Si IC wafers. Active matrix micro‐light‐emitting diode micro‐displays with a resolution of 5000+ pixel per inch were successfully fabricated using Beida Jade Bird Display Limited's monolithic hybrid integration technology. The general fabrication method is described, and the result is presented in this paper. The fabricated monochromatic micro‐light‐emitting diode micro‐displays exhibit improved device performance than do other micro‐display technologies and have great potentials in applications such as portable projectors and near‐to‐eye projection for augmented reality. More importantly, the wafer‐scale monolithic hybrid integration technology offers a clear path for low‐cost mass production of hybrid optoelectronic IC chips. [ABSTRACT FROM AUTHOR]

Three symmetrical donor-acceptor-donor (D-A-D) luminophores ( C1, C2, and C3) with pyrazine derivatives as electron-withdrawing groups have been developed for multistimuli-responsive luminescence switching. For comparison, reference compounds R1 and R2 without the pyrazine moiety have also been synthesized. Intramolecular charge transfer (ICT) interactions can be found for all D-A-D luminophores owing to the electron-withdrawing properties of the two imine nitrogen atoms in the pyrazine ring and the electron-donating properties of the other two amine nitrogen atoms in the two triphenylamine units. Moreover, luminophores C1, C2, and C3 exhibit 'on-off-on' luminescence switching properties in mixtures of water/tetrahydrofuran with increasing water content, which is different from the 'on-off' switching for typical aggregation-caused quenching (ACQ) materials and 'off-on' switching for traditional aggregation-induced emission (AIE) materials. Additionally, upon grinding the pristine samples, luminophores C1, C2, and C3 display bathochromically shifted photoluminescence maxima that can be recovered by either solvent fuming or thermal annealing treatments. The piezofluorochromic (PFC) properties are more pronounced than those for reference compounds R1 and R2, which indicates that D-A molecules have the ability to amplify the PFC effect by tuning the ICT interactions upon tiny structural changes under pressure. Furthermore, the target luminophores demonstrate acid-responsive photoluminescence spectra that can be recovered in either basic or ambient environments. These results suggest that D-A complexes are potential candidates for multistimuli-responsive luminescence switching because their ICT profiles can be facilely tuned with tiny external stimuli. [ABSTRACT FROM AUTHOR]