Energy Transfer Enables 1.53 μm Photoluminescence from Erbium‐Doped TiO 2 Semiconductor Nanocrystals Synthesized by Ar/O 2 Radio‐Frequency Thermal Plasma

Highly crystalline, highly luminescent nanopowders of Er 3+ ‐doped TiO 2 have been successfully synthesized via one‐step Ar/O 2 radio‐frequency thermal plasma processing. Energy transfer from the TiO 2 host to Er 3+ activators has been confirmed by combined means of UV‐vis, excitation, and photoluminescence spectroscopies. As a consequence, bright photoluminescence at ∼1.53 μm was observed from the nanopowders either by directly exciting the Er 3+ activator or by exciting the TiO 2 host lattice. A comparative study shows that the nanopowder of the same system made via coprecipitation lacks the energy transfer. The plasma‐generated nanopowders may thus find applications in optoelectronic devices.