SrZnO <sub> 2 </ Sub> Doped Longwave Ultraviolet Excitation Phosphor Synthesis And Luminescence Properties

In this thesis, SrZnO₂ and its metal-ion-doped luminescent materials have beensynthesized by conventional solid-state reaction and characterized by X-ray diffractionpatterns (XRD), thermogravimetric and differential Thermal analysis (TG-DTA), ultravioletand visible absorption spectrum (UV-Vis), Photoluminescence spectrum (PL) and scanelectron microscopy (SEM). The mechanism of the luminescence of SrZnO₂ has beenprimarily discussed. The luminescent properties, site occupations, energy transfer, criticalconcentrations and their interactions of the doped phosphors have also been investigated.Several promising luminescent materials by long wavelength UV excitation have beenselected. The main conclusions are as follows:The SrZnO₂ crystal phase appears at 900℃and apparently produced at 955℃. TheSrZnO₂ phosphor can be well crystallized above 1000℃although a bit amount of ZnO isalso found by XRD detection. SrZnO₂ exhibits 520 nm green emission originating from therecombination of electrons in singly occupied oxygen vacancies with photoexcited holes inthe valence band of ZnO. SrZnO₂ can efficiently absorb ultraviolet radiation of whichpromote the luminescence of such phosphor. Luminescence properties of SrZnO₂ can begreatly affected by preparation conditions. The best emission intensity can be obtained whenthe sintering temperature, reaction time, anneal mode and ambience are 1000℃, 1 h,quenching cold and nitrogen atmosphere, respectively. SrZnO₂ luminescent material is apromising green-emitting phosphor by long wavelength UV excitation since the excitationand emission peak of which are 380 nm and 520 nm, respectively.SrZnO₂:Tb³⁺ consists of two strong absorption bands, 250 and 262 nm, ranging from230 to 300 nm, which is due to parity allowed 4^f8â†'4f⁷5d transitions. The emission spectraof the phosphor are composed of several bands originating from the transition from 5^D3 to7^F_J and D4 to 7^F_J (J=3-6). The strong green luminescence emission appears at 543 nm.Oneluminescent center may exist in SrZnO₂:Tb³⁺ since the emission spectra are basically thesame with different excitation wavelength.SrZnO₂:Eu³⁺ phosphor shows a broad band centered at 301 nm, which is attributed totransition towards the charger transfer state (CTS) due to Eu-O interaction Moreover, severalweak peaks (365, 385, 395, 415 and 466 nm, respectively) owing to the transitions from F07...