Optical properties and modulated luminescence of metal ion doped phosphors.

摘要

Metal ions (including rare-earth and transition metal ions) doped phosphors have draw much attention due to their applications in light-emitting displays, lasers, optoelectronic devices and biomedicine. The ability to manipulate the spectral properties of phosphors is highly desirable for understanding physical processes of energy transition and widespread applications.;In this thesis, optical properties of rare-earth-doped ferroelectrics are investigated, and the influences of factors such as temperature and site substitution on the phosphors are observed. We also present a new approach to enhance and modulate upconversion emission through applying a relatively low bias voltage to the rare-earth-doped BaTiO3 (BTO) thin films.;We investigated the luminescence properties of rare-earth-doped perovskite type hosts. Photoluminescence (PL) quenching with an increasing Er 3+ doping concentration was investigated based on the structural change and energy transfer of cross-relaxation process in BTO: Er. Temperature dependence of the PL in BTO: Er was revealed, which was associated with phase transitions of BTO host. The results imply that the emission from substituted Er 3+ ions may be used as structural probes for the ferroelectric titanates.;We firstly showed an enhancement and modulation of upconversion emission by applying low bias voltage to the rare-earth-doped BTO thin films on different substrates. The emission intensity at 523 nm of ITO/BTO:Yb/Er/SrRuO3 /SrTiO3 heterostructure under the bias voltage at 10 V is almost 2.7 times as that of the unbiased one. Moreover, the PL intensity of the BTO:Yb/Er can be modulated with ac electric field. This work provides a real-time and dynamic way to control PL under an electric field.;We reported the strain-induced piezoelectric potential stimulated luminescence from ZnS:Mn film on Pb(Mg1/3Nb2/3)O3- xPbTiO3 (PMN-PT) substrate. In contrast to conventional electroluminescence devices including LEDs, such novel light source can be controlled by high-frequency electric-field up to MHz. Moreover, a high-frequency ultrasonic transducer was also realized. The observed phenomena can be used to develop a dual-modal source combing light and ultrasonic signal.;In conclusion, we have utilized the unique characteristics of ferroelectrics to rationally modulate the light emission from metal ions-doped phosphors. These findings will aid further investigation of fundamental research and the widespread applications of the phosphors.