Limits...
Rapid and robust spatiotemporal dynamics of the first-order phase transition in crystals of the organic-inorganic perovskite (C12H25NH3)2PbI4.

Yangui A, Sy M, Li L, Abid Y, Naumov P, Boukheddaden K - Sci Rep (2015)

Bottom Line: The thermal hysteresis loop is 10 K wide, and the interface velocity is constant at V ≈ 1.6 mm s(-1).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.These hitherto unrecognized properties turn this and possibly similar hybrid perovskites into perspective candidates as active medium for microscopic actuation.

View Article: PubMed Central - PubMed

Affiliation: Groupe d'Etudes de la Matière Condensée, Université de Versailles, CNRS UMR 8635, 45 Avenue des Etats Unis, 78035 Versailles, France.

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.

No MeSH data available.


Related in: MedlinePlus

Thermal hysteresis and interface position upon phase transition.(a) Temperature dependence of the green optical density (OD) recorded on heating (red) and cooling (blue). The presence of a hysteresis loop with a width of 10 K confirms the first-order character of the phase transition. (b) Plot of the time-dependence of the front position during heating and cooling, showing a linear trend. Note that the velocity of both processes is nearly identical, V ≈ 1.6 mm s–1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4644986&req=5

f3: Thermal hysteresis and interface position upon phase transition.(a) Temperature dependence of the green optical density (OD) recorded on heating (red) and cooling (blue). The presence of a hysteresis loop with a width of 10 K confirms the first-order character of the phase transition. (b) Plot of the time-dependence of the front position during heating and cooling, showing a linear trend. Note that the velocity of both processes is nearly identical, V ≈ 1.6 mm s–1.

Mentions: The presence of intense excitonic absorption band around 489 nm (2.55 eV) and the notable shift in the optical absorption maxima during the transition (Fig. 1b) were used together with the colorimetric method introduced in ref. 21 to monitor the structural transformation by the “green pixels” of the optical density (OD). Figure 3a depicts the thermal dependence of the spatially averaged OD of the crystal during heating and cooling. The hysteresis loop of 10 K is in accordance with the value determined from the change in crystal size (Fig. 2).


Rapid and robust spatiotemporal dynamics of the first-order phase transition in crystals of the organic-inorganic perovskite (C12H25NH3)2PbI4.

Yangui A, Sy M, Li L, Abid Y, Naumov P, Boukheddaden K - Sci Rep (2015)

Thermal hysteresis and interface position upon phase transition.(a) Temperature dependence of the green optical density (OD) recorded on heating (red) and cooling (blue). The presence of a hysteresis loop with a width of 10 K confirms the first-order character of the phase transition. (b) Plot of the time-dependence of the front position during heating and cooling, showing a linear trend. Note that the velocity of both processes is nearly identical, V ≈ 1.6 mm s–1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644986&req=5

f3: Thermal hysteresis and interface position upon phase transition.(a) Temperature dependence of the green optical density (OD) recorded on heating (red) and cooling (blue). The presence of a hysteresis loop with a width of 10 K confirms the first-order character of the phase transition. (b) Plot of the time-dependence of the front position during heating and cooling, showing a linear trend. Note that the velocity of both processes is nearly identical, V ≈ 1.6 mm s–1.
Mentions: The presence of intense excitonic absorption band around 489 nm (2.55 eV) and the notable shift in the optical absorption maxima during the transition (Fig. 1b) were used together with the colorimetric method introduced in ref. 21 to monitor the structural transformation by the “green pixels” of the optical density (OD). Figure 3a depicts the thermal dependence of the spatially averaged OD of the crystal during heating and cooling. The hysteresis loop of 10 K is in accordance with the value determined from the change in crystal size (Fig. 2).

Bottom Line: The thermal hysteresis loop is 10 K wide, and the interface velocity is constant at V ≈ 1.6 mm s(-1).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.These hitherto unrecognized properties turn this and possibly similar hybrid perovskites into perspective candidates as active medium for microscopic actuation.

View Article: PubMed Central - PubMed

Affiliation: Groupe d'Etudes de la Matière Condensée, Université de Versailles, CNRS UMR 8635, 45 Avenue des Etats Unis, 78035 Versailles, France.

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.

No MeSH data available.


Related in: MedlinePlus