White Light Emission And Energy Transfer Process In Luminescent Glasses

White light emitting diodes（WLEDs）offer new good eco-friendly opportunities in solid state lighting field,giving as a result a significant reduction in global energy consumption and CO2 gases.Additionally,they also exhibit low cost,ease of fine-tuning,solution processability,low toxicity,sufficient flexibility for device fabrications and so on.Their constant improvements in terms of durability,performance and manufacturing require an unstoppable research which lead to get better materials design and fabrication schemes.Then,fields such as artificial lighting,display systems,fluorescent biomedical tools and so on,have had technological improvements.Besides,WLEDs have become a promising component for the next generation of solid-state lighting applications.Here in,Bi³⁺/Eu³⁺single-doped and co-doped SiO₂-Al₂O₃-CaO-B₂O₃-La₂O₃-K₂O glasses were fabricated and further the luminescent properties,energy transfer and thermal stability were systematically investigated.The spectral overlap between emission band of Bi3+and excitation band of Eu3+as well as decay curves of Bi3+emission were analyzed to check the existence of energy transfer from Bi3+to Eu3+.With the increase of Eu³⁺concentration,tunable emitting colors from bluish-green to white and then to orange-red were achieved.White light emission with CIE coordinates（0.348,0.333）was obtained under the excitation of 333 nm.Through the temperature dependent emission spectra,the resistance to thermal quenching of Bi3+/Eu3+was studied.These results indicate that these glasses are potential single-phased white light emitting materials for organic-resin-free W-LEDs.A novel fluorescent intensity ratio（FIR）based optical thermometry using borosilicate glass as host and Tb³⁺/Mn²⁺ions as dual-emitting centers with unique thermal-quenching behaviors has been designed by taking advantage of Tb3+luminescence as reference signal and Mn²⁺as temperature signal.First,the optical and luminescent properties of Tb3+/Mn2+single-doped and co-doped glasses were investigated by series optical spectroscopy method such as absorption spectra,excitation spectra,emission spectra and luminescence decay curves.Secondly,the fluorescence intensity ratio（FIR）technique was used to explore the temperature sensing properties of Tb³⁺/Mn²⁺co-doped glass.Interestingly,the maximum value of relative and absolute sensitivity reaches 0.93%K^-11 and 0.259 K^-11 at 424 and 543 K,respectively.These results suggest that rare earth ions and transition metal co-doped inorganic glasses are excellent platform for optical temperature sensors.