The Photoluminescence Modulation Of Metal Ion Doped Perovskite Oxides

Metal-ion doped luminescent materials have promising applications in various domains such as lighting display,information communication,biological probes,etc.,thus making it crucial to manipulate their luminescent properties.Most existing studies on metal-ion doped luminescent materials concentrate on phosphor materials;however,with the increasing demand for high-density integration and portability of devices,metal-ion doped luminescent films have emerged as a hot topic of research.It is imperative to gain a thorough understanding of how film growth parameters and energy transfer processes of doping ions affect their luminescent properties.Moreover,it is essential to explore how specific film structures can be designed to achieve luminescence modulation,and how large-scale strain can be applied in films to enable more effective insitu and real-time luminescence modulation.These are important research directions in this field.This dissertation addresses the core scientific issues in metal-ion doped oxide films by using laser molecular beam epitaxy technology to fabricate a series of metal-ion doped perovskite oxide films and conducting a systematic investigation on their luminescence modulation by means of oxygen vacancy defects and superlattice structures,piezoelectric strain and mechanical bending strain.The main research contents are as follows:1.The impact of oxygen vacancy defects on the photoluminescence properties of metal-ion doped oxide films was systematically examined.It was discovered that oxygen vacancy defects created new energy levels that facilitated non-radiative energy transfer and reduced luminescence intensity.To inhibit defect formation in films,a ferroelectric superlattice structure was devised and fabricated to simulate a sandwich core-shell nanostructure that enabled spatial separation of doping ions in films and prevented excessive oxygen vacancy defects at high doping concentrations.Furthermore,the superlattice structure optimized the energy transfer pathway for upconversion luminescence and achieved significant enhancement of upconversion emission.2.The piezoelectric strain induced by electric field manipulation of piezoelectric single crystal PMN-PT was utilized to perform in-situ and dynamic modulation of luminescence properties of metal-ion doped oxide films;this resulted in reversible tuning of multi-doping ion multi-band emission intensity;this revealed that piezoelectric strain influenced energy transfer processes and efficiency in films by altering crystal field environment;thus,enabling luminescence modulation.Additionally;lower electric field frequency could generate synchronous luminescence modulation;offering potential for developing electrically controlled variable frequency devices.3.The van der Waals epitaxial growth of perovskite oxide films on mica substrate was achieved;and mechanical bending strain was applied to effectively modulate their luminescence properties;attaining 466.6%increase in luminescence intensity;simultaneously;this dissertation demonstrated that transition metal ions were more responsive to crystal field changes;they could affect energy transfer pathways for rare earth ions when co-doped;thereby realizing substantial light intensity modulation;this finding provides potential application prospects for flexible optoelectronics.4.The technique for preparing self-supporting metal-ion doped oxide films by etching water-soluble sacrificial layer method was investigated;based on this;efficient modulation of strain on selfsupporting film luminescence was accomplished;self-supporting films exhibited high crystalline quality;they could easily undergo large-scale strain gradient application;during bending process for STO:Er selfsupporting film;non-uniform strain generated flexoelectric effect;both effects coupled together to enhance luminescence;under larger strain;ferroelectric polarization and flexoelectric polarization acted together to achieve approximately fourfold increase in luminescence intensity;moreover;transition metal ions displayed remarkable tunability for emission position;after experiencing bending strain;STO:Ni selfsupporting film showed reduced crystal field splitting energy;leading to 76 nm wavelength redshift;STO:Ni self-supporting film exhibited reversible and stable wavelength modulation;providing a material option for developing flexible strain tunable devices.