The crystal structures, pyroelectric properties, and thermal stability of [111]‐oriented 0.5 mol% Mn‐doped 0.36Pb(In1/2Nb1/2)O3‐0.36Pb(Mg1/3Nb2/3)O3‐0.28PbTiO3 (Mn‐0.36PIN‐0.36PMN‐0.28PT) ternary single crystal were investigated. The temperature dependence of the Raman spectra and dielectric properties revealed that the crystal exhibited a rhombohedral (R) structure at room temperature, and ferroelectric R → tetragonal (T) and ferroelectric T to paraelectric cubic (C) phase transitions at 130 and 175°C respectively. The single crystal had a high remnant polarization of Pr = 38 μC cm–2 and coercive field of EC = 12 kV cm–1 at room temperature and a frequency of f = 100 Hz. The values of Pr and EC decreased with increasing temperature, exhibiting anomalies near their phase‐transition temperatures, which coincided with changes in the Raman spectra and dielectric properties. Furthermore, at 25°C and f = 100 Hz, the single crystal had high pyroelectric coefficients of p = 8.7 × 10−4 C m−2 K−1, figures of merit for the current responsivity of Fi = 3.5 × 10−10 m V−1, the voltage responsivity of Fv = 0.08 m2 C−1, and the detectivity of Fd = 30.1 × 10−5 Pa−1/2. These values were weakly dependent on temperature below 120°C. In addition, the room‐temperature pyroelectric coefficients of the ternary single crystal maintain over 83% of the original value at thermal annealing temperatures below 120°C. These outstanding pyroelectric properties, together with high thermal stability, indicate that [111]‐oriented rhombohedral Mn‐0.36PIN‐0.36PMN‐0.28PT ternary single crystal is a new potential candidate for infrared detection applications.
Vertically aligned ZnO-TiO2 hetero-nanostructures constructed of anatase TiO2 nanotubes (NTs) and wurtzite ZnO coatings are fabricated by atomic layer deposition of ZnO coatings on electrochemical anodization formed TiO2 NTs, and their photoelectrochemical activities are studied through photoelectrochemical and electrochemical characterization. Compared with bare TiO2 NTs, the transient photocurrent increases to over 1.5-fold for the annealed ZnO-coated TiO2 NTs under visible illumination. The ZnO-coated TiO2 NTs also show a longer electron lifetime, a lower charge-transfer resistance and a more negative flat-band potential than the bare TiO2 NTs, confirming the improved photoelectrochemical activity due to the enhanced charge separation.
The complex perovskite ferroelectric/antiferroelectric of (Pb1−1.5xLax)(Zr0.42Sn0.40Ti0.18)O3 (PLZST) ceramics have been investigated by Raman scattering spectra from 77 to 480 K. It was found that phase transition occurs between La composition of 2.6% and 2.8% for PLZST ceramics. Softing of A1(TO1) mode and dramatic changes of relative strength from E(TO2) mode are observed at morphotropic phase boundary (MPB). Moreover, it was found that MPB characteristic shows a wider and lower trend of temperature region with increasing La composition. This could be ascribed to the diminishment of the energy barrier and increment of A-cation entropy.
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