The Application Of Rare Earth-doped Luminescent Materials In LED And Perovskite Solar Cells

As a kind of photoluminescent materials,down-shift luminescent materials have the special and unique optoelectronic properties and energy level structure of rare earth ion.It can efficiently absorb and convert high energy photos to low energy photons,and can be used to the field of solid-state lighting and solar cells.White light-emitting diode(WLED),as a new type of light-emitting device,plays a crucial role in lighting,landscape decoration and other fields,because of its advantages of environmental protection,low manufacturing cost and long life.In this paper,based on the exsisted problems of WLED technology,the fluorescent materials with good performance have been made,which can be excited by ultraviolet LED chips.In addition,on the basis of the prepared fluorescent materials,additional studies were conducted on their application in solar cells,with the purpose of improving the light stability of solar cells.The research results are as follows:Part 1:Eu2+,Ce3+,Mn2+ doped phosphors were prepared through high-temperature solid phase method with mature technonlogy and applied to WLED.The studies show that the energy transfer efficiency of Ce3+ is as high as 37%,and the doping of this ion signif1cantly improves the luminous intensity of Eu2+ and Mn2+.By adjusting the concentration of doped ions in SCSPO,the optimal phosphors SCSPO:1%Eu2+,2.5%Ce3+,2%Mn2+was obtained and its quantum efficiency was improved to 36.3%.On the basis of the mechanism of phosphors-conversion LED,the optimal phosphor samples were applied to LED device,and it was found that white light with different chroma could be obtained under the excitation of chips with different wavelengths.Thus,in order to obtain light with different chroma,we can adjust the concentration of doped ions and change the energy of chips,which further proved the extensive application of this phosphor in WLEDs.Part 2:Focusing on the exsisting problems in the preparation of WLEDs with phosphor power,such as low thermal stability,chemical stability and photostability,high thermal expansion coefficient and other defects,improvements and innovation were made.The luminescent glass SBO:Eu,Tb,with high transparency and excellent photochemical satability,was prepared through traditional high-temperature quenching method,in order to replace the traditional phosphor and epoxy resin,and was used in the high-power WLEDs,to enhance the performance of the device from various perspectives.Compared with the phosphor conversion LED(pc-LED),the results show that,the glass-based LED is significantly prominent in anti-aging and thermal radation,and is better than those devices with commercial phosphors in other aspects,such as color rendering index and color difference,which proved the potential application and broad development prospect of glass-based WLED in the field of lighting.Part 3:This work is conducted based on the second part,the photoluminescent glass was applied to the solar cells.The key point is SBO:Eu,Tb,which can convert high-energy ultraviolet light to visible light for perovskite solar cells.On the one hand,it can decrease the danger of ultraviolet radiaton to the preparation of materials in peroskite solar cells.On the other hand,it can increase the light utilization rate,and improve the performance and stability of the device under the dual effect.It can be found from the stability test results that the introduction of luminescent glass SBO:Eu,Tb can efficiently enhance the light stability of the light absorbing material.