Just as the heterojunctions in physics, donor–acceptor (D‐A) heterostructures are an emerging class of photoactive materials fabricated from two semiconductive components at the molecular level. Among them, D‐A hybrid heterostructures from organic and inorganic semiconductive components have attracted extensive attention in the past decades due to their combined advantages of high stability for the inorganic semiconductors and modifiability for the organic semiconductors, which are particularly beneficial to efficiently achieve photoinduced charge separation and transfer upon irradiations. In this review, by analogy with the heterojunctions in physics, a definition of the D‐A heterostructures and their general design and synthetic strategies are given. Meanwhile, the D‐A hybrid heterostructures are focused on and their recent advances in potential applications of photochromism, photomodulated luminescence, and photocatalysis summarized.
Dielectric switches that can be converted between high and lowdielectric states by thermal stimuli have attracted muchi nterest owingt ot heir many potential applications. Currently one main drawbackf or practical application lies in the non-tunability of their switch temperatures (T S ). We report here an ionic co-crystal (Me 3 NH) 4 [Ni(NCS) 6 ]t hat contains amultiply rotatable Me 3 NH + ion and asolely rotatable one due to am ore spacious supramolecular cage for the former one. This compound undergoes an isostructural order-disorder phase transition and it can function as af requency-tuned dielectric switch with highly adjustable T S ,w hich is further revealed by the variable-temperature structure analyses and molecular dynamics simulations.I na ddition, the distinct arrangements and molecular dynamics of two coexisting Me 3 NH + ions confined in different lattice spaces as well as the notable offset effect on the promoting/hindering of dipolar reorientation after dielectric transition provideararely observed but fairly good model for understanding and modulating the dipole motion in crystalline environment.
A series of thermotropic main-chain liquidcrystalline (LC) ionomers were prepared, which contained potassium sulfonate groups pendent to the chains. The polymers were prepared in an esterifying reaction with potassium ion contents ranging between 0 and 3.9 wt %. The content of potassium ion was characterized by spectrophotometric analysis with sodium tetraphenylboron as the titrant. Chemical structures were determined by various experimental techniques including Fourier transform IR spectroscopy and 1 H-NMR. LC properties were characterized by differential scanning calorimetry, polarizing optical microscopy, and X-rays. All of the polymers displayed nematic or smectic mesophases. With increasing potassium sulfonate ionic concentration in the polymers, the melting temperatures and isotropic transition temperatures changed little, whereas the temperature of the smectic A-nematic phase transition increased. The ionic aggregation was tangled with the rigid mesogenic groups of LC segments to form multiple block domains, leading the soft main chains to fold and form a lamellar structure due to their electrostatic interactions.
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