Low-temperature route to nanoscale P3N5 hollow spheres

Nanoscale hollow spheres of amorphous phosphorus nitride P3N5 were synthesized by reacting PCl3 with NaN3 at 150-250 degreesC. Transmission electron microscope images show that the hollow spheres have a diameter of 150-350 nm, and the thickness of the shell is 20 nm. A very small amount of curly films were also found in the sample prepared at 150 degreesC. The infrared spectrum indicates a high degree of purity. X-ray photoelectron spectroscopy indicates the presence of P and N, with a molar ratio of 1:1.62 for RN. Ultraviolet-visible absorption spectroscopy shows an absorption band at 265-315 nm. Under photoluminescent excitation at 230 nm, the P3N5 emits ultraviolet light at 305 nm. With a band gap of 4.28 eV, the products may be a wide gap semiconductor. A possible mechanism and the influence of temperature on the formation of the hollow spheres are also discussed.