Fabrication, Up-Conversion Luminescence And Temperature Sensing Of Erbium Ions Doped Oxyfluoride Glass Ceramics

Erbium (Er3+) ions doped luminescent materials have been continuously esteemed due to their potential applications in photo-communication, lighting, luminescent displays, up-conversion, quantum cutting, biological fluorescent labels and optical amplifiers. Transparent fluoride nanocrystals based transparent oxyfluoride glass-ceramics are a new type of luminescent nanostructured composite for rare earth ions doping. They combine advantages of excellent mechanical and chemical stability of oxide glasses and low phonon energy environment of fluoride nanocrystals and have been widely researched and are regard as favorable candidates for up-conversion. In this case, the investigation on the fabrication, up-conversion properties and applications of novel Er3+ ions doped transparent oxyfluoride glass-ceramics becomes an important project. The main contents in this work are listed below.1. Er3+ ions doped NaYbF4 oxyfluoride glass-ceramics:Er3+ ions-doped transparent oxyfluoride glass-ceramics containing NaYbF4 nanocrystals were successfully fabricated by melt-quenching technique and further heat-treatments. These glass-ceramics are excellent materials for up-conversion emitting. Excited by 980 nm laser source, the up-conversion intensity in glass-ceramics was obviously enhanced compared with precursor glass, which could be accredited to the incorporation of Er3+ ions into low-phonon-energy NaYbF4 nanocrystals that could reduce the nonradiative transition rate of Er3+ ions. Our results suggest that NaYbF4 glass-ceramics may play an important role in transparent up-conversion optical functional materials.2. Er3+ ions doped NasGd9F32 oxyfluoride glass-ceramics:novel Er3+ ions-doped transparent oxyfluoride glass-ceramics containing novel cubic NasGd9F32 nanocrystals were successfully fabricated by melt-quenching technique and further heat-treatments for the first time. The crystalline phase of NasGd9F32 nanocrystals does not change with increasing heat-treatment temperature, which indicates that they have good thermal stability. The obvious Stark splitting, enhanced characteristic up-conversion emissions (1300 times for red emission,1000 times for green emission), slower rise time and longer luminescence lifetimes in glass-ceramics reveal the priority incorporation of Er3+ into NasGd9F32 nanocrystals with low phonon energy and shorter Er3+-Er3+distances. For up-conversion mechanisms, ESA processes are dominant in PG sample and ET processes are dominant in GC samples. Our investigation indicates thermal-stable NasGd9F32 glass-ceramics may be used as potential transparent optical functional materials in the future.3. Er3+ ions doped transparent Sr2YbF7 oxyfluoride glass-ceramics:novel Er3+ions-doped transparent glass-ceramics containing tetragonal Sr2YbF7 nanocrystals were fabricated by melt-quenching technique in air atmosphere with further heat-treatment. Up-conversion spectra and fluorescence decay curves were used to depict their luminescent properties and the up-conversion mechanism. Their microstructure and transparency were investigated by XRD, TEM, absorption spectra. Excited by 980 nm, samples exhibit excellent up-conversion emissions of Er3+ ions. FIR technique was used to investigate the dependence of two green up-conversion emissions and temperature. Our results reveal that Sr2YbF7:Er3+ glass-ceramics have larger thermally coupled energy levels (TCEL) gap and higher relative temperature sensitivity, which certifies that Sr2YbF7:Er3+ glass-ceramics have great potential in optical temperature sensing.