Approaching Piezoelectric Response of Pb-Piezoelectrics in Hydrothermally Synthesized Bi_0.5(Na_1–xK_x)_0.5TiO₃ Nanotubes

Abstract

A large piezoelectric coefficient of 76 pm/V along the diameter direction, approaching that of lead-based piezoelectrics, is observed in hydrothermally synthesized Pb-free Bi(NaK)TiO nanotubes. The 30-50 nm diameter nanotubes are formed through a scrolling and wrapping mechanism without the need of a surfactant or template. A molar ratio of KOH/NaOH = 0.5 for the mineralizers yields the Na/K ratio of ∼0.8:0.2, corresponding to an orthorhombic-tetragonal (O-T) phase boundary composition. X-ray diffraction patterns along with transmission electron microscopy analysis ascertain the coexistence of orthorhombic and tetragonal phases with (110) and (001) orientations along the nanotube length direction, respectively. Na NMR spectroscopy confirms the higher degree of disorder in Bi(NaK )TiO nanotubes with O-T phase coexistence. These findings present a significant advance toward the application of Pb-free piezoelectric materials.

Doping Process of 2D Materials Based on the Selective Migration of Dopants to the Interface of Liquid Metals

“…The corresponding XRD peak from the SnO nanosheets at ≈32° shifts slightly to the lower diffraction angles when the Bi 2 O 3 concentration increases, due to the incorporation of the larger unit cell Bi 2 O 3 in the SnO nanosheets. [ 39 ] This peak in the nanosheets is hardly visible once the ratio of Bi in bulk increased to ≥80%, due to the creation of a higher concentration of randomly distributed α‐Bi 2 O 3 structures within the SnO nanosheets. The increased incorporation of α‐Bi 2 O 3 reduces the possibility of parallel re‐stacking of the layers and also enhances the formation of separate SnO clusters.…”

Physicochemical Characterization of a Na–H–F Thermal Battery Material

“…At greater F – content, it may be thermodynamically favorable for multiple crystalline phase segregation to occur, which is evidenced by the reduced dispersion along the Q IS axis. Within this context, it is likely that the broadening for the isotropic peak (iii) observed for NaH 0.50 F 0.50 is not a result of disorder since it would be expected to also result in a concomitant dispersion of the quadrupolar shift, which is seen, for example, in disordered pervoskites. , Instead, it is likely a result of multiple 23 Na sites within the NaH/F family that are not sufficiently chemically resolved and therefore have a large spectral overlap. Finally, we note that the peak marked (iv) for x = 0.5 having the lowest chemical shift is likely some unreacted “pure” NaF phase.…”

Surface silanized MWCNTs doped PVDF nanocomposite with self-organized dipoles: an intrinsic study on the dielectric, piezoelectric, ferroelectric, and energy harvesting phenomenology

“…54 The hysteresis phase switching by 180 upon application of a DC bias is attributed to the dipoles (self-organized) being parallel to the applied electric eld, which further conrms the ferroelectric nature of the nanocomposites. 55 The remanent polarization was investigated for the prepared nanocomposites using the hysteresis loop or P-E (polarization vs. electric eld) curve, as depicted in Fig. S10 † (refer to ESI † Section S7).…”