eduzhai > Physical Sciences > Materials Sciences >

Ferroelectric properties of single component molecular crystals above room temperature

  • gufeng
  • (0) Download
  • 20211125
  • Save

... pages left unread,continue reading

Document pages: 6 pages

Abstract: Ferroelectrics are electrically active materials that can store and switch their polarity (ferroelectricity), sense temperature changes (thermoelectricity), exchange electrical and mechanical functions (piezoelectric) and manipulate light (through optical nonlinearity and electro-optic effect): all these functions have practical applications. π - conjugated topological switches in organic molecules, such as ketone enol conversion, have long been considered as a means to realize these phenomena in molecular assembly and crystals. 1. Saffron acid is a component of black dye 2. Recently, it was found that it has hydrogen bonded polar structure 3 in the crystalline state. Here, we prove that the application of electric field can consistently arrange the molecular polarity in the crystalline croconic acid, as indicated by an increase of optical second harmonic generation, and produce a well-defined polarization hysteresis at room temperature. To make this simple pentagonal molecule ferroelectric, we switched the π-bond topology using synchronized proton transfer instead of rigid-body rotation. Of the organic ferroelectrics, this molecular crystal exhibits the highest spontaneous polarization (∼20 μC cm-2) in spite of its small molecular size, which is in accord with first-principles electronic-structure calculations. Such high polarization, which persists up to 400 K, may find application in active capacitor and nonlinear optics elements in future organic electronics.

Please select stars to rate!


0 comments Sign in to leave a comment.

    Data loading, please wait...