Fabrication and characterization of La2O3–Fe2O3–Bi2O3 nanopowders: Effects of La2O3 addition on structure, optical, and radiation-absorption properties

In this study, we fabricated and characterized six new nanopowders representing variations of La2O3-Fe2O3-Bi2O3, i.e., 100Bi(2)O(3), 30Fe(2)O(3)-70Bi(2)O(3), 3La(2)O(3)-27Fe(2)O(3)-70Bi(2)O(3), 7La(2)O(3)-23Fe(2)O(3)-70Bi(2)O(3), 10La(2)O(3)-20Fe(2)O(3)-70Bi(2)O(3), and 20La(2)O(3)-10Fe(2)O(3)-70Bi(2)O(3) (represented by 100B, 30F70B, 3L27F70B, 10L20F70B, and 20L10F70B, respectively). These nanopowders were prepared by the microwave-assisted hydrothermal synthesis method. Saponin extract from soapnuts was used as the nanoparticle capping agent. The structural, optical, and gamma radiation characteristics were measured, calculated, and analysed, respectively. The chemical structures of the nanocomposites influenced their optical and radiation shielding characteristics. The optical bandgaps of the 100B, 30F70B, 3L27F70B, 7L23F70B, 10L20F70B, and 20L10F70B nanopowders were 3.16, 3.13, 3.43, 3.45, 3.46, and 3.58 eV, respectively. The ranges of the mass attenuation coefficients of the nanopowders were computed, using XCOM, to be 0.0412-5.1624, 0.0401-4.5406, 0.0401-4.5285, 0.0401-4.5129, 0.0401-0.5015, and 0.0400-4.4156 cm(2)/g, respectively, and the ranges of mass energy absorption coefficients were found to be 0.0232-1.7525, 0.0228-1.5484, 0.0228-1.5598, 0.0288-1.5746, 0.0228-1.5853, and 0.0227-1.6192 cm(2)/g, respectively, for photon energies in the range of 0.1-10 MeV. The order of the dose rate trend was as follows: 30F70B < L27F70B < 7L23F70B < 10L20F70B < 20L10F70B. Analysis of the photon interaction parameters showed that the synthesized nanopowders could function well as fillers in radiation-shielding matrices.