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A new series of ladder‐type heteroarenes electro‐optic (EO) chromophores based on unique fused oligothiophene, oligofuran, and oligopyrrole bridge with a strong push–pull effect were designed, and their distinctive electric structure and nonlinear optical (NLO) properties were investigated by multiple methods, including DOS analysis, CPKS method, SOS model, TSM model, and hyperpolarizability density analysis. Interestingly, it is found that the introduction of different strengths of donor and acceptor moieties, the nature of ladder‐type heteroarenes bridge, and the medium polarity play critical roles in achieving ultra‐large hyperpolarizabilities. Encouragingly, the DN1‐6Fu‐AS1 and DN1‐6Py‐AS1 both exhibit ultra‐large βprj values (up to 12965.5 × 10−30 esu) and βtot value (up to 13238.2 × 10−30 esu), owing to their exceptionally low transitions energy and large variation of dipole moment. The DO2‐6Fu‐AO2, DO2‐6Th‐AO2, DO2‐6Fu‐AS1, and DO2‐6Th‐AS1, exhibit very deep HOMO levels, which are expected to have superior air stability and effectively prevent large leakage currents. Hirshfeld surface analysis and interaction region indicator analysis were employed to explore the noncovalent interactions in the dimer. The DO2‐6Fu‐AS1 and DO2‐6Py‐AS1 show the outstanding electro‐optical Pockels effect, and DN1‐6Fu‐AO2 exhibit large SHG responses. These unique and brand‐new push‐pull ladder‐type heteroarenes chromophores are promising candidates for chip‐scale EO modulators, and electronic and photonic devices in emerging communication, energy, analog, and digital technologies. [ABSTRACT FROM AUTHOR]

Development of organic nonlinear optical materials has become progressively more important due to their emerging applications in new‐generation photonic devices. A novel series of chromophores based on innovative thiophene and furan‐fused cyclopentadienyl bridge with various powerful donor and acceptor moieties were designed and theoretically investigated for applications in nonlinear optics. To unravel the structure–property relationship between this new push‐pull conjugated systems and their nonlinear optical property, multiple methods, including density of states analysis, coupled perturbed Kohn–Sham (CPKS) method, sum‐over‐states (SOS) model, the two‐level model (TSM), hyperpolarizability density analysis, and the (hyper)polarizability contribution decomposition, were performed to comprehensively investigated the nonlinear optical and electronic properties of this new π‐system. Due to excellent charge transfer ability of new bridge and distinctive structure of donor and acceptor, the designed chromophores exhibit deep HOMO levels, low excitation energy, high dipole moment difference and large hyperpolarizability, indicating the appealing air‐stable property and remarkable electrooptic performance of them. Importantly, THQ‐CS‐A3 and PA‐CS‐A3 shows outstanding NLO response properties with βtot value of 6953.9 × 10−30 and 5066.0 × 10−30 esu in AN, respectively. The influence of the push‐pull strength, the heterocycle and the π‐conjugation of new bridge on the nonlinear optical properties of this novel powerful systems are clarified. This new series of chromophores exhibit remarkable electro‐optical Pockels and optical rectification effect. More interestingly, PA‐CS‐A3 and THQ‐CS‐A2 also show appealing SHG effect. This study will help people understand the nature of nonlinear optical properties of innovative heteroarene‐fused based cyclopentadienyl chromophores and offer guidance for the rational design of chromophores with outstanding electrooptic (EO) performance in the future. [ABSTRACT FROM AUTHOR]

Novel chromophores Ch1–8 based verbenone bridge with various strong donors and acceptors were designed for applications in nonlinear optics, and the nonlinear optical (NLO) properties of those verbenone‐type chromophores were systematically investigated using the bond length alteration (BLA) theory, two states model (TSM) and sum‐over‐states (SOS) model. The results show that several verbenone‐based chromophores possess remarkably large molecular second‐order hyperpolarizabilities, which is due to its electron distribution close to the cyanine limit, the appropriate strength of acceptor, rather large change in dipole moment and low excitation energy. Computed hyperpolarizability (βtot) of Ch6 also approach an outstanding 2922 × 10−30 esu in TFE. The hyperpolarizability density analyses and two states model (TSM) were carried out to make a further insight into the origination of molecular nonlinearity of this unique system, suggesting that tuning structure of acceptor and polarity of the medium have great influence on the second‐order nonlinear optical properties. More importantly, chromophores Ch1–Ch8 exhibited distinct features in two‐dimensional second order NLO responses, and the strong electro‐optical Pockels effect and optical rectification responses. The excellent electronic sum frequency generations (SFG) and difference frequency generations (DFG) effect are observed in these verbenone‐type chromophores. These chromophores have a possibility to be appealing second‐order nonlinear optical (NLO) materials, data storage materials and DSSCs materials from the standpoint of large β values, high LHE, and excellent two‐dimensional second order NLO responses. [ABSTRACT FROM AUTHOR]

Chicken infectious anaemia virus (CIAV) has been identified as the causative agent of chicken infectious anaemia (CIA), causing huge economic losses to the poultry industry globally. In this study, a total of 573 clinical samples were collected from 197 broiler farms in 17 provinces of China during 2020-2021. Among them, 375 samples (375/573, 65.4%) were positive for CIAV by real-time PCR. The positive rate of CIAV detection between different regions of China ranged from 46.67% (North China) to 81.25% (Central China). The nucleotide sequences of the VP1 gene were obtained for 91 CIAV strains, whole genome sequencing was successful for 72 out of 91 strains. Phylogenetic analysis based on the VP1 gene revealed that 91 CIAV strains currently circulating in China belong to three genotypes (II, IIIa and IIIb), and most of the CIAV strains belong to genotype IIIa. Phylogenetic analysis of the whole genome showed that 71 CIAV strains belong to genotype IIIa, and one strain belongs to genotype II. Sequence analysis showed several amino acid substitutions in both the VP1, VP2 and VP3 proteins. Our results enhance the understanding of the molecular characterization of CIAV infection in China. RESEARCH HIGHLIGHTS A molecular systematic survey of CIAV in China during 2020-2021. CIAV genotype IIIa is the predominant genotype in China. [ABSTRACT FROM AUTHOR]

We designed and synthesized two novel azobenzene functionalized poly(aryl ether)s (PAEs), PAE-azo-1 and PAE-azo-2, from a new azobenzene monomer via nucleophilic aromatic substitution polycondensation. This direct polymerization approach via azobenzene monomer has the advantages of controlling the distribution and amount of the azobenzene chromophores in the polymer. Both of the polymers showed very good thermal stability and excellent solubility for future application in the electronics industry. These polymers were fabricated as films by simple spin-coating and both of them were then prepared as sandwich memory devices. PAE-azo-1 and PAE-azo-2 exhibit write-once-read-many-times-type memory behavior, which can be encoded as "0" and "1," and possess the low operation voltage below −3.0 V. The memory mechanism was investigated through ultraviolet–visible optical absorption spectrum and the cyclic voltammetry. These obtained results indicate that the novel azobenzene functionalized PAEs are a promising candidate for low power consumption and high-performance materials for data storage. [ABSTRACT FROM AUTHOR]

This study reports the fabrication and characterization of polymer resistive switching memory devices fabricated from poly(ether sulfone)s (PESs), containing carboxylic functional groups for hydrogen bonding with disperse red 1. PES-based supramolecular memory devices exhibited write-once read-many-times-type memory effects, with low switching threshold voltages below −5.0 V and high ON/OFF current ratios of 105. It is the first time that the concept of azobenzene supramolecular PES based on hydrogen bonding for electrical memory device application was investigated. A possible switching mechanism based on the charge transfer interaction was proposed through molecular simulation, optical absorption, and cyclic voltammetry. These results render the PES-based supramolecular memory devices as promising components for high-performance polymer memory devices. [ABSTRACT FROM AUTHOR]