Synthesis,Luminescence Properties And Applications Of Mn⁴⁺ Doped Fluoride Red Phosphors

White light emitting diodes?WLEDs?are known as a new generation of solid-state light sources in the 21st century.Currently,the mass production of commercial WLEDs depends on the combination of yellow phosphor Y₃Al₅O₁₂:Ce³⁺(YAG:Ce³⁺)with blue InGaN chip.However,the lack of red light component in the spectrum limits the application of WLEDs,and the most direct way to solve this problem is to add red phosphor on this basis.Recently,Mn⁴⁺-doped fluoride red phosphors have attracted wide attention because of their low cost,high luminous efficiency,low reabsorption,etc.However,the external quantum efficiency of such phosphors is generally low,causing it difficult to meet the commercial requirements,besides,the synthetic process currently requires the consumption of a large amount of HF,and HF is harmful to the human body and the environment.Therefore,in view of the above situation,this paper focuses on exploring,synthesizing and studying novel Mn⁴⁺-doped fluoride red phosphors with high efficience,mild synthesis and environmental friendlines.The main contents and research results are as follows:?1?Mn⁴⁺activated ternary-alkaline fluoride red phosphors K₂XAlF₆:Mn⁴⁺?X=Na,Li?were produced by co-precipitation method,and the properties such as phase and morphology,luminescence performance,moisture resistance,thermal stability and device performance of WLEDs were analyzed comprehensively.Both K₂XAlF₆?X=Na,Li?matrixes can achieve the characteristic red emission of Mn⁴⁺and strong zero lines appear in the spectram due to the non-equivalent doping,the concentration quenching of K₂XAlF₆:Mn⁴⁺?X=Na,Li?systems at room temperature may be dominated by dipole-dipole interaction.The thermal stability,moisture resistance and device performance of two phosphors are significantly better than some previously reported Mn⁴⁺-doped binary fluoride red phosphors.Among them,K₂NaAlF₆:Mn⁴⁺has greater potential for application in the field of white LEDs due to superior overall performance.?2?Rb₂XF₆:Mn⁴⁺?X=Ti,Zr?red phosphors were synthesized by co-precipitation method using H₂O as the solvent instead of traditional HF,which greatly reduced the total consumption of HF in the synthetic process.Firstly,the optimization of samples was achieved by investigating the effect of types of solvent,additive order of raw materials,doping concentration of activator,amount of solvent added and the reaction stirring time on the luminescence intensity of the samples.Furthermore,the systems'phase and morphology,luminescence performance,thermal stability,moisture resistance and device performance of WLEDs were systematically analyzed.Both types of phosphors can be used as red-light components to obtain high quality warm WLEDs,but it is worth noting that Rb₂TiF₆:Mn⁴⁺has more excellent luminescence,thermal stability,moisture resistance and device performance,moreover,the variable drive current and temperature examinations also show that Rb₂TiF₆:Mn⁴⁺red powder can be used to synthesize high power WLEDs with preferable heat resistance.