Effect of Pressure on Crystal Structure and Optical Properties of Bi2O3 Nanoparticles

Nano materials have gained importance recently in several medical and technological applications due to their unique size-dependent properties that make these materials superior and indispensable. Bi2O3 nanoparticles are used... [ view full abstract ]

Nano materials have gained importance recently in several medical and technological applications due to their unique size-dependent properties that make these materials superior and indispensable. Bi2O3 nanoparticles are used in a number of applications such as fungicidal agent, gas sensor and semiconductor. Recent studies show that bulk Bi2O3 exhibit several polymorphs and the crystal structure is sensitive to external pressure and temperature conditions. Despite the importance of this material, the polymorphs of nanoparticles of Bi2O3 are less known to date when compared to the bulk. In order to understand the new Bi2O3 nanoparticle phases and polymorphs, we have investigated the crystal structure of bismuth oxide (beta-Bi2O3) nanoparticles (average particle size of 100nm) under high pressure conditions up to 50 GPa. The powder x-ray diffraction experiments were performed using high resolution synchrotron x-rays in the angle dispersive geometry with a diamond anvil high pressure cell at the Advanced Photon Source (APS), Argonne National Laboratory. Raman spectroscopy measurements were conducted up to similar pressure ranges to complement the x-ray results. Our experiments clearly indicate that the nanoparticles undergo pressure induced amorphization above 15 GPa. The phase change behavior is found to be comparable with bulk Bi2O3. We will discuses the structural stability and vibrational properties in detail.