Upconversion Luminescence And Application Exploration From Rear-earth Ions Doped Materials Based On Two-wavelength Excitation

Energy crisis and information communication congestion problems closely related to the production and life of people are becoming serious with the acceleration of modern informatization process,which require us to search for new,green and sustainable materials and to design facile physical strategy to replace the traditional methods at the cost of energy consumption and environmental pollution.Trivalent rare-earth ions doped inorganic luminescent materials based on two-wavelength excitation can break the bottlenecks such as low luminescence efficiency under conventionally single-wavelength light source excitation,showing a broad application potential in signature research fields of energy,information,and biological in the 21 st century.The main work in this dissertation includes: Firstly,we studied and discussed the upconversion luminescence mechanism of trivalent lanthanide ions single-doped materials based on two-wavelength excitation through consulting a large number of literature.Secondly,different trivalent lanthanide ions single-doped luminescent materials,including phosphors,glass,and glass-ceramic were designed,optimized,and prepared to investigate the upconversion luminescence and application based on two-wavelength excitation.Finally,we launched the investigation on the upconversion luminescence of rare-earth ions single-doped materials based on two-wavelength excitation and its application in the realms of solar cells,white light modulation and white light laser,fast-slow optical switch modulation,nonlinear optical modulation,and so on.We found many novel physical phenomena and made a series of research achievements during the theoretical analysis,optical performance characterization and application demonstration,and the details are summarized as follows:?1?Upconversion luminescence and its application exploration in the field of solar cells based on two-wavelength,tri-wavelength,and broadband excitation.The research contents are mainly concentrated on: 1)For the motivation of the enhancement of the energy conversion efficiency of solar cells,we proposed the concept of highly efficient upconversion luminescence and discussed its physical mechanism in depth based on two-wavelength,tri-wavelength,and broadband excitation.2)We studied and compared the upconversion luminescence feature of Er³⁺:Ba Cl₂,Er³⁺:Ba F₂ and Er³⁺:NaYF₄ phosphors under two-color field excitation of 808 and 980 nm laser,and successfully demonstrated the feasibility of harvesting broadband near-infrared sunlight to improve the power conversion efficiency of solar cells on the amorphous silicon solar cells coupled with Er³⁺:BaCl₂ upon two-wavelength excitation.3)We investigated the upconversion luminescence property of glass ceramics containing Er³⁺:LaF₃ nanocrystals upon simultaneous tri-wavelength excitation of 808,980,and 1530 nm laser,and discussed the microscope mechanism in depth,and further demonstrated the feasibility of harvesting broadband near-infrared sunlight to improve the power conversion efficiency of solar cells on the amorphous silicon solar cells coupled with the Er³⁺-doped glass ceramics upon three-color field excitation.4)We studied and compared the upconversion luminescence performance of Er³⁺:BaCl₂ and Er³⁺:Na YF₄ phosphors under excitation of concentrated incoherent broadband near-infrared sunlight with wavelength > 800 nm,and further compared the upconversion luminescence character of BaCl₂ phosphors doped with other rear-earth ions,and finally demonstrated successfully the photocurrent response profile of amorphous silicon solar cells attached with BaCl₂ phosphors doped with rear-earth ions under excitation of concentrated incoherent broadband near-infrared sunlight,suggesting that,Er³⁺:BaCl₂ phosphor,in comparison with other materials,is the most potential upconvresion materials for the enhancement of power conversion efficiency in next-generation solar cells.5)We investigated the upconversion luminescence property of single-phase Ce VO₄ powder without dopants,and put forward the concept for the enhancement of power conversion efficiency in solar cells by harvesting broadband near-infrared sunlight through black radiation luminescence of Ce VO₄ powder,and ultimately demonstrated successfully its photocurrent response feature.?2?Upconversion luminescence and its application exploration for white light modulation and white light laser in Pr³⁺-doped glass ceramics based on two-wavelength excitation.The research contents are mainly concentrated on: We proposed the concept of white light modulation from multi-color upconversion luminescence of Pr³⁺ single-doped materials by using simultaneous two-wavelength excitation approach of 850 and 980 nm laser,and then successfully demonstrated the upconversion white light modulation in Pr³⁺-doped germanate oxyfluoride glass ceramics,and finally investigated the sensitivity of the upconversion white light modulation performance in glass and glass ceramics to the concentration of Pr³⁺ ions.?3?Blue,green,and red upconversion luminescence optical switch modulation with fast and slow optical response speed in rear-earth ions single-doped glass ceramics based on two-wavelength excitation.The research contents are mainly concentrated on: 1)We proposed the concept of manipulating the blue/green upconversion luminescence optical switch modulation with fast and slow optical response speed in Tm³⁺ or Er³⁺ single-doped glass ceramics by utilizing the two-wavelength excitation strategy,and obtained enhanced upconversion luminescence among which the blue/green upconversion luminescence intensities respectively enhanced by 800% and 1500% in comparison with that upon single-wavelength excitation,and further validated the possibility of the concept we proposed via theory simulation and calculation.2)We put forward the concept of modulating the single-band red upconversion luminescence optical switch modulation with fast and slow optical response speed in Ho³⁺ single-doped glass ceramics by taking advantage of the two-wavelength excitation tactic.Firstly,we confirmed the feasibility of the concept we proposed by simulation and calculation in the angle of theory;Then,we successfully demonstrated the red upconversion luminescence optical switch modulation with fast and slow optical response speed in Ho³⁺-doped germanate oxyfluoride glass ceramics in experiment;Finally,comparing to that upon single-wavelength excitation,the enhancement of as high as 2500% of the red upconversion luminescence intensity has been achieved.?4?Nonlinear optics properties and its application exploration form Er³⁺ single-doped glass ceramics based on excitation of lasers with different NIR wavelengths.The research contents are mainly concentrated on: We firstly put forward a concept of modulating the nonlinear transmittance of Er³⁺-doped materials by using excitation of disparate NIR wavelengths for the development of bidirectional optical switches.Then,we systematically investigated on the tunable nonlinear transmittance of the Er³⁺ single-doped GCs containing La F₃ nanocrystals upon excitation of NIR lasers with disparate wavelengths via theoretical simulation and calculation,experimental confirmation,electronic energy level transition and luminescence dynamical analysis,validating the feasibility of this idea;Finally,the bidirectional optical switching for the “on-off” toggle effect has been successfully demonstrated by selectively tailoring the nonlinear transmittance of the Er³⁺ single-doped GCs materials through excitation of various NIR wavelengths.