Browsing by Author "Ren, Shenqiang"

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    Magnet-in-ferroelectric crystals exhibiting photomultiferroicity
    Wang, Zhongxuan; Wang, Qian; Gong, Weiyi; Chen, Amy; Islam, Abdullah; Quan, Lina; Woehl, Taylor J.; Yan, Qimin; Ren, Shenqiang (National Academy of Sciences, 2024-04-16)
    Growing crystallographically incommensurate and dissimilar organic materials is fundamentally intriguing but challenging for the prominent cross-correlation phenomenon enabling unique magnetic, electronic, and optical functionalities. Here, we report the growth of molecular layered magnet-in-ferroelectric crystals, demonstrating photo-manipulation of interfacial ferroic coupling. The heterocrystals exhibit striking photomagnetization and magnetoelectricity, resulting in photomultiferroic coupling and complete change of their color while inheriting ferroelectricity and magnetism from the parent phases. Under a light illumination, ferromagnetic resonance shifts of 910 Oe are observed in heterocrystals while showing a magnetization change of 0.015 emu/g. In addition, a noticeable magnetization change (8% of magnetization at a 1,000 Oe external field) in the vicinity of ferro-to-paraelectric transition is observed. The mechanistic electric-field-dependent studies suggest the photoinduced ferroelectric field effect responsible for the tailoring of photo-piezo-magnetism. The crystallographic analyses further evidence the lattice coupling of a magnet-in-ferroelectric heterocrystal system.
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    Reversible Ferroelectric Polarization Modulation of Chiral Molecular Ferroelectrics by Circularly Polarized Light
    Wang, Zhongxuan; Wang, Qian; Quan, Lina; Ren, Shenqiang (Wiley, 2025-01-21)
    The optical modulation of ferroelectric polarization constitutes a transformative, non-contact strategy for the precise manipulation of ferroelectric properties, heralding advancements in optically stimulated ferroelectric devices. Despite its potential, progress in this domain is constrained by material limitations and the intricate nature of the underlying mechanisms. Recent studies have achieved efficient regulation of ferroelectric polarization and thermal conductivity in chiral ferroelectric thin films through the application of left- and right-handed circularly polarized light (LCP and RCP). Differential absorption of circularly polarized light (CPL) induces nonequilibrium carrier dynamics, generating distinctive interfacial electrostatic fields that enable precise control of ultrathin ferroelectric films. For (R)-BINOL−DIPASi and (S)-BINOL−DIPASi (C26H26O2Si), polarization changes surpass 23%, exhibiting opposite response under LCP and RCP excitation. In R chiral films, remnant polarization decreases from 1.05 µC cm−2 under LCP to 0.85 µC cm−2 under RCP, whereas in S chiral films, polarization increases from 0.85 µC cm−2 under LCP to 0.98 µC cm−2 under RCP. This reversible modulation facilitates reliable switching between ON and OFF states, presenting the potential of chiral ferroelectric materials for flexible, high-speed integrated photonic sensor technologies.
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    Supramolecular Metal Halide Complexes for High-Temperature Non-linear Optical Switches
    Wang, Qian; Jin, Jianbo; Wang, Zhongxuan; Ren, Shenqiang; Ye, Qingyu; Dou, Yixuan; Liu, Sunhao; Morris, Amanda; Slebodnick, Carla; Quan, Lina (American Chemical Society, 2024-02-23)
    Nonlinear optical (NLO) switching materials, which exhibit reversible intensity modulation in response to thermal stimuli, have found extensive applications across diverse fields including sensing, photoelectronics, and photonic applications. While significant progress has been made in solid-state NLO switching materials, these materials typically showcase their highest NLO performance near room temperature. However, this performance drastically deteriorates upon heating, primarily due to the phase transition undergone by the materials from noncentrosymmetric to centrosymmetric phase. Here, we introduce a new class of NLO switching materials, solid-state supramolecular compounds 18-Crown-6 ether@Cu2Cl4·4H2O (1·4H2O), exhibiting reversible and stable NLO switching when subjected to near-infrared (NIR) photoexcitation and/or thermal stimuli. The reversible crystal structure in response to external stimuli is attributed to the presence of a weakly coordinated bridging water molecule facilitated by hydrogen bonding/chelation interactions between the metal halide and crown-ether supramolecules. We observed an exceptionally high second-harmonic generation (SHG) signal under continuous photoexcitation, even at temperatures exceeding 110 °C. In addition, the bridging water molecules within the complex can be released and recaptured in a fully reversible manner, all without requiring excessive energy input. This feature allows for precise control of SHG signal activation and deactivation through structural transformations, resulting in a high-contrast off/on ratio, reaching values in the million-fold range.