title: Rapid and robust spatiotemporal dynamics of the first-order phase transition in crystals of the organic-inorganic perovskite (C12H25NH3)2PbI4.
abstract: The dynamics of the thermally induced first-order structural phase transition in a high-quality single crystal of the organic-inorganic perovskite (C12H25NH3)2PbI4 was investigated by optical microscopy. The propagation of the straight phase front (habit plane) during the phase transition along the cooling and heating pathways of the thermal hysteresis was observed. The thermochromic character of the transition allowed monitoring of the thermal dependence of average optical density and aided the visualization of the interface propagation. The thermal hysteresis loop is 10 K wide, and the interface velocity is constant at V ≈ 1.6 mm s(-1). The transition is accompanied with sizeable change in crystal size, with elongation of ~6% along the b axis and compression of ~ -2% along the a axis, in excellent agreement with previously reported X-ray diffraction data. The progression of the habit plane is at least 160 times faster than in spin-crossover materials, and opens new prospects for organic-inorganic perovskites as solid switching materials. Moreover, the crystals of (C12H25NH3)2PbI4 are unusually mechanically robust and present excellent resilience to thermal cycling. These hitherto unrecognized properties turn this and possibly similar hybrid perovskites into perspective candidates as active medium for microscopic actuation.
authors.affiliation: Groupe d'Etudes de la Matière Condensée, Université de Versailles, CNRS UMR 8635, 45 Avenue des Etats Unis, 78035 Versailles, France.|Laboratoire de Physique Appliquée, Faculté des Sciences de Sfax, Route de Soukra km 3.5 3000 Sfax, Tunisia.
authors.forename: Aymen
authors.initials: A
authors.lastname: Yangui
authors.affiliation: Groupe d'Etudes de la Matière Condensée, Université de Versailles, CNRS UMR 8635, 45 Avenue des Etats Unis, 78035 Versailles, France.
authors.forename: Mouhamadou
authors.initials: M
authors.lastname: Sy
authors.affiliation: New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates.
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.affiliation: Laboratoire de Physique Appliquée, Faculté des Sciences de Sfax, Route de Soukra km 3.5 3000 Sfax, Tunisia.
authors.forename: Younes
authors.initials: Y
authors.lastname: Abid
authors.affiliation: New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates.
authors.forename: Panče
authors.initials: P
authors.lastname: Naumov
authors.affiliation: Groupe d'Etudes de la Matière Condensée, Université de Versailles, CNRS UMR 8635, 45 Avenue des Etats Unis, 78035 Versailles, France.
authors.forename: Kamel
authors.initials: K
authors.lastname: Boukheddaden