Synthesis of image nanoparticles by pulsed laser ablation in deionized water and optical properties

We report the first synthesis of calcium molybdate (image) nanoparticles by pulsed laser ablation (PLA) in deionized water. The crystalline phase, particle morphology, particle size distribution, absorbance, optical band-gap and photoluminescence (PL) were investigated. Stable colloidal suspensions consisting of well-dispersed image nanoparticles with narrow size distribution could be obtained without any surfactant. Optical absorption edge is located near 270 nm, which is blue-shifted about 70 nm than that of reported data in bulk crystals. The estimated optical energy band-gap was 4.7 eV and PL spectrum was positioned in blue-shifted region around 430 nm compared with emission at 525 nm of bulk image target. The observed band-gap widening and blue-shift of PL emission could be ascribed to the quantum-size effect due to the very small size of the image nanoparticles prepared by PLA in deionized water.