Effects of microstructures on the compression behavior and phase transition routine of In₂O₃ nanocubes under high pressures

Abstract

The differences between the compression behaviors of nanocrystal systems and their bulk counterparts are generally attributed to the size and morphology effects. However, these effects may not be simply employed to deal with the contradictory results about In2O3 bulk and nanomaterials under high pressures. In this work, we intend to show that other than size and morphology, the effects of microstructure should play a key role in the compression behavior and phase transition routine of In2O3 cubical-shaped nanocrystals under high pressures. Two samples of In2O3 nanocubes, which have almost the same size, shape and exposed facets, are subjected to high pressure at room temperature. The In2O3 nanocubes with a lower density of microstructures undergo a first order phase transition at about 18.9 GPa, and the two phases coexist when the pressure is released. Whereas the In2O3 nanocubes with a higher density of microstructures show no sign of such a phase transition at pressures up to 33.4 GPa, a change of elastic properties at about 8.8 GPa may be observed instead. Thus, it is anticipated that controlling the microstructures of nanomaterials may be a potential route to modulate their structural and elastic behaviors under pressures. Fig. 1 (a,b) The SEM image and high-magnification TEM image of uniform c-In2O3 nanocubes (S1) synthesized at 210 °C with the heating rate of 4 °C/min. (c,d) The SEM image and high-magnification TEM image of uniform c-In2O3 nanocubes (S2) synthesized at 180 °C with the heating rate of 8 °C/min.

Experimental Observation of the High Pressure Induced Substitutional Solid Solution and Phase Transformation in Sb2S3

“…First, it is important to have in view the compositions, geometric shapes, sizes, and microstructures, of the samples employed. These features play an important role in the compression behaviors of materials under high pressures 23 . The second point concerns with the experimental details, such as the pressurizing procedures, the pressure intervals, the accelerating rate of pressures, and the pressure-maintaining period of time, etc.…”

Pressure-Induced Phase Transitions in Sesquioxides

“…HP studies in group-13-SOs have been conducted on the five compounds. Al 2 O 3 , also known as alumina, is by far the most studied compound [85][86][87][88][89][90][91][92][93][94][95][96][97][98][99], followed by In 2 O 3 [100][101][102][103][104][105][106][107][108][109], Ga 2 O 3 [107,[110][111][112][113][114], and B 2 O 3 [115][116][117][118][119][120][121]. Finally, Tl 2 O 3 has been the least studied compound [122].…”

Structural and vibrational properties of corundum-type In2O3nanocrystals under compression

“…86 On the other hand, a significantly lower bulk modulus (148±5 GPa) compared to theoretical calculations (169.4 GPa) has been recently observed in c-In2O3 nanocrystals with a high defect density under compression with a 4:1 methanol-ethanol mixture as PTM. 60 In that work, authors claimed that the different bulk modulus of two nanocrystalline samples with similar sizes and morphologies were due to their different defect densities. Another possibility is that the change in compressibility observed above 8 GPa in In2O3 nanocrystals could be due to non-hydrostatic conditions as it was reasoned for nanocrystalline TiO2 anatase.…”

“…Even if several works have been devoted to the study of In2O3 nanocrystals at HP, most of them have focused on nanocrystals of cubic bixbyite-type In2O3, [58][59][60] and only a small part have been devoted to study nanocrystals of rhombohedral corundum-type In2O3. 49,50,59 In fact, a different stability range of the rhomobohedral phase under compression has been observed depending on the sample size.…”