Magnon-driven interfacial magnetoelectric coupling in Co/PMN-PT multiferroic heterostructures.

Magnon-driven interfacial magnetoelectric coupling in Co/PMN-PT multiferroic heterostructures is investigated at room temperature. The electric field controlled ferromagnetic resonance field possesses a loop-like curve, with a large resonance field shift between positive and negative remanent polarizations, which confirms a non-volatile strong magnetoelectric coupling. However, with a non-magnetic Ta layer inserted at the Co/PMN-PT interface, a piezostrain-induced butterfly-like curve of the resonance field versus applied electric field of the Co/Ta/PMN-PT multiferroic heterostructure is observed. Further, the non-volatile behavior of the resonance field changing with the applied electric field can be obtained, consistent with the result of polarization versus applied electric field curve, which can be attributed to the magnon-driven interfacial magnetoelectric coupling, showing a strong correlation of magnetization of Co thin film and the polarization of PMN-PT. The result is promising for the design of future multiferroic devices.

Enhanced Sensitivity and Piezochromic Contrast through Single-Direction Extension of Molecular Structure.

Two piezochromic materials containing phenanthro[9,10-d]imidazole and tetraphenylethylene (M1 and M2) were developed. A supra-amplification piezochromic effect originating from their various long-to-short axis ratios was discovered in high-pressure experiments. Based on the linear relationship between applied pressure and emission-peak wavelength during pressurizing and depressurizing cycles, quantitative sensitivity for piezochromism could be denoted. M2 displayed higher piezochromic contrast (102 nm) and better sensitivity (11.19 nm GPa-1 ) than M1 (69 nm and 6.12 nm GPa-1 ), which helps to develop a more comprehensive general strategy to evaluate pressure-responsive performance.

E/Z isomerization, solvatachromism and aggregation-induced emission enhancement of donor-acceptor type oligo(p-phenylene vinylene)s.

A donor-acceptor molecule, PICNDSB, with cyclopenta[b]indole as the donor and (1,4-phenylene)bis(3-phenylacrylonitrile) as the acceptor, is designed and synthesized. PICNDSB shows typical aggregation-induced emission characteristics. The photoluminescence quantum yield of PICNDSB in dilute THF was only 0.7% and reaches 51.4% in the solid state. Compared with its analogue CzCNDSB, PICNDSB possesses stronger intramolecular charge transfer properties, as revealed from CV measurements, theoretical calculations, and their fluorescence behaviors. Correspondingly, the relatively more efficient electron-donating terminal group of cyclopenta[b]indole endows the molecule with a much higher two-photon absorption cross section of 1286 GM compared to CzCNDSB (357 GM).

Magnon-tuning non-volatile magnetic dynamics in a CoZr/PMN-PT structure.

Magnon-tuning non-volatile magnetic dynamics is investigated in a CoZr/PMN-PT structure by measuring ferromagnetic resonance at room temperature. The electric-field control of ferromagnetic resonance shows loop-like behavior, which indicates non-volatile electric-field control of the magnetism. Further, fitting the curves of in-plane rotating angle versus ferromagnetic resonance field under different electric fields shows that the effective magnetic field changes in loop-like manner with the electric field. The resulting change in non-volatile saturation magnetization with electric field is consistent with that of a polarization electric field curve. A 1.04% change of saturation magnetization is obtained, which can be attributed to a magnon-driven magnetoelectric coupling at the CoZr/PMN-PT interface. This magnon-driven magnetoelectric coupling and its dynamic magnetic properties are significant for developing future magnetoelectric devices.

Projective-anticipating, projective, and projective-lag synchronization of time-delayed chaotic systems on random networks.

We study projective-anticipating, projective, and projective-lag synchronization of time-delayed chaotic systems on random networks. We relax some limitations of previous work, where projective-anticipating and projective-lag synchronization can be achieved only on two coupled chaotic systems. In this paper, we realize projective-anticipating and projective-lag synchronization on complex dynamical networks composed of a large number of interconnected components. At the same time, although previous work studied projective synchronization on complex dynamical networks, the dynamics of the nodes are coupled partially linear chaotic systems. In this paper, the dynamics of the nodes of the complex networks are time-delayed chaotic systems without the limitation of the partial linearity. Based on the Lyapunov stability theory, we suggest a generic method to achieve the projective-anticipating, projective, and projective-lag synchronization of time-delayed chaotic systems on random dynamical networks, and we find both its existence and sufficient stability conditions. The validity of the proposed method is demonstrated and verified by examining specific examples using Ikeda and Mackey-Glass systems on Erdos-Renyi networks.

Unique piezochromic fluorescence behavior of organic crystal of carbazole-substituted CNDSB.

CzCNDSB with a highly twisted conformation in the solid state is constructed. Single crystal measurements prove that it possesses an inside pore with a diameter of 8 Å and further forms a long-range orderly arrayed channel. CzCNDSB can sense external pressure from 1.0 atm to 9.21 GPa, accompanied by color changes from green to red with excellent reversibility and reproducibility.

An ambipolar organic field-effect transistor based on an AIE-active single crystal with a high mobility level of 2.0 cm(2) V(-1) s(-1).

Organic field-effect transistors (OFETs) based on an aggregation-induced emission (AIE) material were fabricated using a calcium-gold asymmetric electrode system. The devices showed very high and balanced mobility, reaching 2.50 and 2.10 cm(2) V(-1) s(-1), respectively, for electron and hole. Strong green electroluminescence from the single-crystal side edge was observed from all the devices. This work demonstrates that AIE active materials could not only achieve high luminescence, but also be used in light emitting transistors and achieve very high mobility.

Twisted D-π-A solid emitters: efficient emission and high contrast mechanochromism.

Triphenylacrylonitrile and diarylamine based D-π-A luminogens exhibit typical AIE characteristics with high solid state efficiency up to unity and switchable mechanochromism with high contrast, which render them multifunctional materials for versatile applications in optical storage, volatile organic compound (VOC) detection, OLEDs, etc.

Synergy between twisted conformation and effective intermolecular interactions: strategy for efficient mechanochromic luminogens with high contrast.

A strategy towards efficient mechanochromic luminogens with high contrast is developed. The twisted propeller-like conformations and effective intermolecular interactions not only endow the luminogens with AIE characteristics and high efficiency in the crystalline state, but also render them to undergo conformational planarization and disruption in intermolecular interactions upon mechanical stimuli, resulting in remarkable changes in emission wavelength and efficiency.